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DESCRIPTION
The WM8956 is a low power, high quality stereo DAC designed for portable multimedia applications. Stereo class D speaker drivers provide 1W per channel into 8 loads with a 5V supply. Low leakage, excellent PSRR and pop/click suppression mechanisms also allow direct battery connection to the speaker supply. Flexible speaker boost settings allow speaker output power to be maximised while minimising other analogue supply currents. A highly flexible input configuration for up to three stereo sources is integrated, with a complete microphone interface. External component requirements are drastically reduced as no separate microphone, speaker or headphone amplifiers are required. Stereo 24-bit sigma-delta DACs are used with low power oversampling digital interpolation filters and a flexible digital audio interface. The master clock can be input directly or generated internally by an onboard PLL, supporting most commonly-used clocking schemes. The WM8956 operates at analogue supply voltages down to 2.7V, although the digital supplies can operate at voltages down to 1.71V to save power. The speaker supply can operate at up to 5.5V, providing 1W per channel into 8 loads. Unused functions can be disabled using software control to save power. The WM8956 is supplied in a very small and thin 5x5mm QFN package, ideal for use in hand-held and portable systems.
WM8956
Hi-Fi DAC with 1W Stereo Class D Speaker Drivers and Headphone Drivers
FEATURES
* * * * DAC SNR 99dB (`A' weighted), THD -87dB at 48kHz, 3.3V Pop and click suppression 3D Enhancement Stereo Class D Speaker Driver * <0.1% THD with 1W per channel into 8 BTL speakers * 70dB PSRR @217Hz * 87% efficiency (1W output) * Flexible internal switching clock On-chip Headphone Driver * 40mW output power into 16 at 3.3V * Capless mode support * THD+N -70dB at 20mW, SNR 99dB with 16 load Microphone Interface * Pseudo differential for high noise immunity * Integrated low noise MICBIAS Low Power Consumption * 16mW headphone playback (2.7V / 1.8V supplies) Low Supply Voltages * Analogue 2.7V to 3.6V (Speaker supply up to 5.5V) * Digital core and I/O: 1.71V to 3.6V On-chip PLL provides flexible clocking scheme Sample rates: 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48 5x5x0.9mm QFN package
*
* * * * * *
APPLICATIONS
* * * Mobile multimedia Portable media / DVD players Games consoles
WOLFSON MICROELECTRONICS plc
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Preliminary Technical Data, July 2007, Rev 2.1
Copyright (c)2007 Wolfson Microelectronics plc
WM8956 TABLE OF CONTENTS
Preliminary Technical Data
DESCRIPTION .......................................................................................................1 FEATURES.............................................................................................................1 APPLICATIONS .....................................................................................................1 TABLE OF CONTENTS .........................................................................................2 PIN CONFIGURATION...........................................................................................3 ORDERING INFORMATION ..................................................................................3 PIN DESCRIPTION ................................................................................................4 ABSOLUTE MAXIMUM RATINGS.........................................................................5 RECOMMENDED OPERATING CONDITIONS .....................................................5 ELECTRICAL CHARACTERISTICS ......................................................................6 OUTPUT PGA GAIN.............................................................................................10 TYPICAL POWER CONSUMPTION ....................................................................11 SIGNAL TIMING REQUIREMENTS .....................................................................12
SYSTEM CLOCK TIMING............................................................................................ 12 AUDIO INTERFACE TIMING - MASTER MODE ......................................................... 12 AUDIO INTERFACE TIMING - SLAVE MODE ............................................................ 13 CONTROL INTERFACE TIMING - 2-WIRE MODE ..................................................... 14
INTERNAL POWER ON RESET CIRCUIT ..........................................................15 DEVICE DESCRIPTION.......................................................................................17
INTRODUCTION.......................................................................................................... 17 INPUT SIGNAL PATH.................................................................................................. 18 OUTPUT SIGNAL PATH.............................................................................................. 26 ANALOGUE OUTPUTS ............................................................................................... 32 ENABLING THE OUTPUTS ......................................................................................... 35 HEADPHONE OUTPUT ............................................................................................... 36 CLASS D SPEAKER OUTPUTS .................................................................................. 37 VOLUME UPDATES .................................................................................................... 38 HEADPHONE JACK DETECT ..................................................................................... 40 THERMAL SHUTDOWN .............................................................................................. 42 GENERAL PURPOSE INPUT/OUTPUT ...................................................................... 42 DIGITAL AUDIO INTERFACE...................................................................................... 43 AUDIO INTERFACE CONTROL .................................................................................. 47 CLOCKING AND SAMPLE RATES .............................................................................. 50 CONTROL INTERFACE .............................................................................................. 57 POWER MANAGEMENT ............................................................................................. 57
REGISTER MAP...................................................................................................60
REGISTER BITS BY ADDRESS .................................................................................. 61
DIGITAL FILTER CHARACTERISTICS ...............................................................73
DAC FILTER RESPONSES ......................................................................................... 73 DE-EMPHASIS FILTER RESPONSES ........................................................................ 75
APPLICATIONS INFORMATION .........................................................................76
RECOMMENDED EXTERNAL COMPONENTS........................................................... 76
PACKAGE DRAWING..........................................................................................79 IMPORTANT NOTICE ..........................................................................................80
ADDRESS:................................................................................................................... 80
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Preliminary Technical Data
WM8956
PIN CONFIGURATION
32
31
30
29
28
27
26
25 24 23 22 21
MICBIAS LINPUT3/JD2 LINPUT2 LINPUT1 RINPUT1 RINPUT2 RINPUT3/JD3 DCVDD
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SPKGND1 SPK_LN SPK_RP SPKVDD2 SPKGND2 SPK_RN SDIN SCLK
TOP VIEW
20 19 18 17
ORDERING INFORMATION
ORDER CODE WM8956GEFL/V WM8956GEFL/RV Note: Reel quantity = 3500 TEMPERATURE RANGE -40C to +85C -40C to +85C PACKAGE 32-lead QFN (5x5x0.9mm) (Pb-free) 32-lead QFN (5x5x0.9mm) (Pb-free, tape and reel) MOISTURE SENSITIVITY LEVEL MSL3 MSL3 PEAK SOLDERING TEMPERATURE 260C 260C
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WM8956 PIN DESCRIPTION
PIN NO 1 2 NAME MICBIAS LINPUT3 / JD2 TYPE Analogue Output Analogue Input Microphone bias
Preliminary Technical Data
DESCRIPTION Left channel line input / Left channel positive differential MIC input / Jack detect input pin Left channel line input / Left channel positive differential MIC input Left channel single-ended MIC input / Left channel negative differential MIC input Right channel single-ended MIC input / Right channel negative differential MIC input Right channel line input / Right channel positive differential MIC input Right channel line input / Right channel positive differential MIC input / Jack detect input pin Digital core supply Digital ground (Return path for both DCVDD and DBVDD) Digital buffer (I/O) supply Master clock Audio interface bit clock Audio interface DAC left / right clock DAC digital audio data GPIO1 pin Leave this pin floating Control interface clock input Control interface data input / 2-wire acknowledge output Right speaker negative output Ground for speaker drivers 2 Supply for speaker drivers 2 Right speaker positive output Left speaker negative output Ground for speaker drivers 1 Left speaker positive output Supply for speaker drivers 1 Midrail voltage decoupling capacitor Analogue ground (Return path for AVDD) Right output (Line or headphone) Mono, left, right or buffered midrail output for capless mode Left output (Line or headphone) Analogue supply Die Paddle (Note 1)
3 4 5 6 7
LINPUT2 LINPUT1 RINPUT1 RINPUT2 RINPUT3 / JD3
Analogue Input Analogue Input Analogue Input Analogue Input Analogue Input
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Note: 1. 2.
DCVDD DGND DBVDD MCLK BCLK DACLRC DACDAT GPIO1 DNC SCLK SDIN SPK_RN SPKGND2 SPKVDD2 SPK_RP SPK_LN SPKGND1 SPK_LP SPKVDD1 VMID AGND HP_R OUT3 HP_L AVDD GND_PADDLE
Supply Supply Supply Digital Input Digital Input / Output Digital Input / Output Digital Input Digital Input / Output Do not connect Digital Input Digital Input/Output Analogue Output Supply Supply Analogue Output Analogue Output Supply Analogue Output Supply Analogue Output Supply Analogue Output Analogue Output Analogue Output Supply
It is recommended that the QFN ground paddle should be connected to analogue ground on the application PCB. Refer to the application note WAN_0118 on "Guidelines on How to Use QFN Packages and Create Associated PCB Footprints"
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Preliminary Technical Data
WM8956
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at or beyond these limits. Device functional operating limits and guaranteed performance specifications are given under Electrical Characteristics at the test conditions specified. ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage of this device. Wolfson tests its package types according to IPC/JEDEC J-STD-020B for Moisture Sensitivity to determine acceptable storage conditions prior to surface mount assembly. These levels are: MSL1 = unlimited floor life at <30C / 85% Relative Humidity. Not normally stored in moisture barrier bag. MSL2 = out of bag storage for 1 year at <30C / 60% Relative Humidity. Supplied in moisture barrier bag. MSL3 = out of bag storage for 168 hours at <30C / 60% Relative Humidity. Supplied in moisture barrier bag. The Moisture Sensitivity Level for each package type is specified in Ordering Information. CONDITION Supply voltages (excluding SPKVDD1 and SPKVDD2) SPKVDD1, SPKVDD2 Voltage range digital inputs Voltage range analogue inputs Operating temperature range, TA Storage temperature after soldering Notes 1. 2. 3. 4. 5. Analogue, digital and speaker grounds must always be within 0.3V of each other. All digital and analogue supplies are completely independent from each other (i.e. not internally connected). DCVDD must be less than or equal to AVDD and DBVDD. AVDD must be less than or equal to SPKVDD1 and SPKVDD2. SPKVDD1 and SPKVDD2 must be high enough to support the peak output voltage when using DCGAIN and ACGAIN functions, to avoid output waveform clipping. Peak output voltage is AVDD*(DCGAIN+ACGAIN)/2. MIN -0.3V -0.3V DGND -0.3V AGND -0.3V -40C -65C MAX +4.5V +7V DBVDD +0.3V AVDD +0.3V +85C +150C
RECOMMENDED OPERATING CONDITIONS
PARAMETER Digital supply range (Core) Digital supply range (Buffer) Analogue supplies range Speaker supply range Ground SYMBOL DCVDD DBVDD AVDD SPKVDD1, SPKVDD2 DGND, AGND, SPKGND1, SPKGND2 MIN 1.71 1.71 2.7 2.7 0 TYP MAX 3.6 3.6 3.6 5.5 UNIT V V V V V
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WM8956 ELECTRICAL CHARACTERISTICS
Preliminary Technical Data
Test Conditions DCVDD = 1.8V, DBVDD = 3.3V, AVDD = SPKVDD1 = SPKVDD2 = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, PGA gain = 0dB, 24-bit audio data unless otherwise stated. PARAMETER Full-scale Input Signal Level - note this changes in proportion to AVDD SYMBOL VINFS TEST CONDITIONS L/RINPUT1,2,3 Single-ended L/RINPUT1/2 or L/RINPUT1/3 Full Differential MIC L/RINPUT2 or L/RINPUT3 Pseudo Differential MIC Mic PGA equivalent input noise Input resistance (Note that input boost and bypass path resistances will be seen in parallel with PGA input resistance when these paths are enabled) L/RINPUT1 0 to 20kHz, +30dB gain +30dB PGA gain Differential or singleended MIC configuration 0dB PGA gain Differential or singleended MIC configuration -17.25dB PGA gain Differential or singleended MIC configuration (Constant for all gains) Differential MIC configuration Max boost gain L/RINPUT2/3 to boost 0dB boost gain L/RINPUT2/3 to boost Min boost gain L/RINPUT2/3 to boost Max bypass gain L/RINPUT2/3 to bypass Min bypass gain L/RINPUT2/3 to bypass MIN TYP 1.0 0 0.5 -6 1.0 0 150 3 MAX UNIT Vrms dBV Vrms dBV Vrms dBV uV k
Analogue Inputs (LINPUT1, RINPUT1, LINPUT2, LINPUT3, RINPUT2, RINPUT3)
L/RINPUT1
49
k
L/RINPUT1
87
k
L/RINPUT2, L/RINPUT3 L/RINPUT2, L/RINPUT3 L/RINPUT2, L/RINPUT3 L/RINPUT2, L/RINPUT3 L/RINPUT3 L/RINPUT3 Input capacitance MIC Programmable Gain Amplifier (PGA) Programmable Gain Min Programmable Gain Max Programmable Gain Step Size Mute Attenuation Selectable Input Gain Boost Gain Boost Steps
85
k
7.5 13 37 17 70 10 -17.25 30
k k k k k pF dB dB dB dB
Guaranteed monotonic LMIC2B = 0 and RMIC2B = 0 Input from PGA Input from L/RINPUT2 or L/RINPUT3
0.75 85
0, 13, 20, 29, MUTE -12, -9, -6, -3 0, 3, 6, MUTE
dB dB
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Preliminary Technical Data
WM8956
Test Conditions DCVDD = 1.8V, DBVDD = 3.3V, AVDD = SPKVDD1 = SPKVDD2 = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, PGA gain = 0dB, 24-bit audio data unless otherwise stated. PARAMETER Signal to Noise Ratio (A-weighted) Total Harmonic Distortion Plus Noise SYMBOL SNR THD+N TEST CONDITIONS AVDD = 3.3V AVDD = 2.7V Full Scale Input Signal, AVDD = 3.3V Full Scale Input Signal, AVDD = 2.7V Signal to Noise Ratio (A-weighted) Total Harmonic Distortion Plus Noise SNR THD+N AVDD = 3.3V AVDD = 2.7V Full Scale Input Signal, AVDD = 3.3V Full Scale Input Signal, AVDD = 2.7V Signal to Noise Ratio (A-weighted) Total Harmonic Distortion Plus Noise SNR THD+N AVDD = 3.3V AVDD = 2.7V Full Scale Input Signal, AVDD = 3.3V Full Scale Input Signal, AVDD = 2.7V MIN TYP 99 99 -93 0.002 -94 0.002 102 102 -93 0.002 -94 0.002 104 104 -96 0.002 -97 0.001 dB % dB dB % dB dB % MAX UNIT dB
Analogue Inputs (LINPUT1/2 Differential, RINPUT1/2 Differential) to Line-Out (HP_L, HP_R, OUT3 with 10k / 50pF load)
Analogue Inputs (LINPUT2, RINPUT2) via Boost to Line-Out (HP_L, HP_R, OUT3 with 10k / 50pF load)
Analogue Inputs (LINPUT3, RINPUT3) via Bypass to Line-Out (HP_L, HP_R, OUT3 with 10k / 50pF load)
Analogue Inputs (LINPUT1, RINPUT1, LINPUT2, RINPUT2, LINPUT3, RINPUT3) to Line-Out (HP_L, HP_R, OUT3 with 10k / 50pF load) Channel Separation 1kHz full scale signal to HP_L/R outputs via L/RINPUT1, MIC amp (single-ended) and boost 1kHz full scale signal to HP_L/R outputs via L/RINPUT2 and boost 1kHz full scale to HP_L/R outputs via L/RINPUT3 and boost Boost / Bypass Separation (Quiescent LINPUT3/RINPUT3 to HP outputs via bypass) 1kHz on LINPUT2/RINPUT2 to input boost mixer via MIC PGA 1kHz on LINPUT1/RINPUT1 to input boost mixer via MIC PGA Channel Matching 1kHz signal 98 dB
90
dB
96
dB
90
dB
90
dB
0.2
dB
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WM8956
Preliminary Technical Data
Test Conditions DCVDD = 1.8V, DBVDD = 3.3V, AVDD = SPKVDD1 = SPKVDD2 = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, PGA gain = 0dB, 24-bit audio data unless otherwise stated. PARAMETER 0dB Full scale output voltage Mute attenuation Channel Separation 1kHz, full scale signal L/RINPUT3 to headphone outputs via bypass SNR THD+N THD AVDD=3.3V AVDD=2.7V AVDD=3.3V AVDD=2.7V AVDD=3.3V AVDD=2.7V Channel Separation Output Power per channel Total Harmonic Distortion + Noise PO THD+N 1kHz full scale signal Headphone Output (HP_L, HP_R, using capacitors unless otherwise specified) Output power is very closely correlated with THD; see below. AVDD=2.7V, RL=32 PO=5mW AVDD=2.7V, RL=16 PO=5mW AVDD=3.3V, RL=32, PO=20mW AVDD=3.3V, RL=16, PO=20mW Signal to Noise Ratio (A-weighted) Output Power Total Harmonic Distortion + Noise (DAC to speaker outputs) SNR AVDD = 3.3V AVDD = 2.7V PO THD+N 92 -78 0.013 -75 0.018 -72 0.025 -70 0.032 99 98 dB dB % SYMBOL TEST CONDITIONS MIN TYP AVDD/3.3 86 110 MAX UNIT Vrms dB dB
Headphone Outputs (HP_L, HP_R)
DAC to Line-Out (HP_L, HP_R, OUT3 with 10k / 50pF load) Signal to Noise Ratio (A-weighted) Total Harmonic Distortion Plus Noise Total Harmonic Distortion 99 98 -85 -90 -87 -92 110 dB dB dB dB
Speaker Outputs (SPK_LP, SPK_LN, SPK_RP, SPK_RN with 8 bridge tied load) Output power is very closely correlated with THD; see below PO =200mW, RL = 8, SPKVDD1=SPKVDD2 =3.3V; AVDD=3.3V PO =320mW, RL = 8, SPKVDD1=SPKVDD2 =3.3V; AVDD=3.3V PO =500mW, RL = 8, SPKVDD1=SPKVDD2 =5V; AVDD=3.3V PO =1W, RL = 8, SPKVDD1=SPKVDD2 =5V; AVDD=3.3V Total Harmonic Distortion + Noise (LINPUT3 and RINPUT3 to speaker outputs) THD+N PO =200mW, RL = 8, SPKVDD1=SPKVDD2 =3.3V; AVDD=3.3V PO =320mW, RL = 8, SPKVDD1=SPKVDD2 =3.3V; AVDD=3.3V PO =500mW, RL = 8, SPKVDD1=SPKVDD2 =5V; AVDD=3.3V PO =1W, RL = 8, SPKVDD1=SPKVDD2 =5V; AVDD=3.3V -78 0.013 -72 0.025 -75 0.018 -70 0.032 -78 0.013 -72 0.025 -75 0.018 -70 0.032 dB % dB % dB % dB % dB % dB % dB % dB %
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Preliminary Technical Data
WM8956
Test Conditions DCVDD = 1.8V, DBVDD = 3.3V, AVDD = SPKVDD1 = SPKVDD2 = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, PGA gain = 0dB, 24-bit audio data unless otherwise stated. PARAMETER Signal to Noise Ratio (A-weighted) (DAC to speaker outputs) SYMBOL SNR TEST CONDITIONS SPKVDD1=SPKVDD2 =3.3V; AVDD=3.3V; RL = 8, ref=2.0Vrms SPKVDD1=SPKVDD2 =5V; AVDD=3.3V; RL = 8, ref=2.8Vrms Signal to Noise Ratio (A-weighted) (LINNPUT3 and RINPUT3 to speaker outputs) SNR SPKVDD1=SPKVDD2 =3.3V; AVDD=3.3V; RL = 8, ref=2.0Vrms SPKVDD1=SPKVDD2 =5V; AVDD=3.3V; RL = 8, ref=2.8Vrms ISPKVDD SPKVDD1=SPKVDD2 =5V; All other supplies disconnected SPKVDD1=SPKVDD2 =5V; All other supplies 0V Power Supply Rejection Ratio (100mV ripple on SPKVDD1/SPKVDD2 @217Hz) Analogue Reference Levels Midrail Reference Voltage Microphone Bias Bias Voltage VMICBIAS 3mA load current MBSEL=1 3mA load current MBSEL=0 Bias Current Source Output Noise Voltage Digital Input / Output Input HIGH Level Input LOW Level Output HIGH Level Output LOW Level Input capacitance Input leakage -0.9 VIH VIL VOH VOL IOL=1mA IOH-1mA 10 0.9 0.9xDBVDD 0.1xDBVDD 0.7xDBVDD 0.3xDBVDD V V V V pF uA IMICBIAS Vn 1K to 20kHz 15 -5% -5% 0.9xAVDD 0.65xAVDD + 5% + 5% 3 V V mA nV/Hz VMID -3% AVDD/2 +3% V PSRR DAC to speaker playback LINPUT3/RINPUT3 to speaker playback MIN TYP 90 MAX UNIT dB
92
dB
90
dB
92
dB
Speaker Supply Leakage current
1
uA
1
uA
80 80
dB dB
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WM8956 OUTPUT PGA GAIN
Output PGA Gains (Target gain, not measured)
20 40 60 80 100 120 140
Preliminary Technical Data
10 0
-10 0 -20 Gain (dB) -30 -40 -50 -60 -70 -80
Volume Register Setting
Figure 1 Output PGA Gains (LOUT1VOL, ROUT1VOL, SPKLVOL, SPKRVOL)
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Preliminary Technical Data
WM8956
TYPICAL POWER CONSUMPTION
Mode Off (Default state at power-up, no clocks) AVDD (V) 2.7 3 3.3 3.6 2.7 3 3.3 3.6 2.7 3 3.3 3.6 2.7 3 3.3 3.6 2.7 3 3.3 3.6 2.7 3 3.3 3.6 2.7 3 3.3 3.6 2.7 3.3 3.3 3.3 2.7 3.3 3.3 3.3 2.7 3.3 3.3 3.3 2.7 3.3 3.3 3.6 SPKVDD (V) 2.7 3 3.3 5.5 2.7 3 3.3 5.5 2.7 3 3.3 5.5 2.7 3 3.3 5.5 2.7 3 3.3 5.5 2.7 3 3.3 5.5 2.7 3 3.3 5.5 2.7 3.3 5 5.5 2.7 3.3 5 5.5 2.7 3.3 5 5.5 2.7 3.3 5 5.5 DBVDD (V) 1.71 1.8 3.3 3.6 1.71 1.8 3.3 3.6 1.71 1.8 3.3 3.6 1.71 1.8 3.3 3.6 1.71 1.8 3.3 3.6 1.71 1.8 3.3 3.6 1.71 1.8 3.3 3.6 1.71 3.3 3.3 3.3 1.71 3.3 3.3 3.3 1.71 3.3 3.3 3.3 1.71 3.3 3.3 3.6 DCVDD (V) 1.71 1.8 1.8 3.6 1.71 1.8 1.8 3.6 1.71 1.8 1.8 3.6 1.71 1.8 1.8 3.6 1.71 1.8 1.8 3.6 1.71 1.8 1.8 3.6 1.71 1.8 1.8 3.6 1.71 1.8 1.8 1.8 1.71 1.8 1.8 1.8 1.71 1.8 1.8 1.8 1.71 1.8 1.8 3.6 IAVDD ISPKVDD IDBVDD IDCVDD Total (mA) (mA) (mA) (mA) (mW) 0.0314 0 0 0 0.085 0.0326 0 0 0 0.098 0.033 0 0 0 0.109 0.0345 0 0 0 0.124 0.0086 0 0 0 0.023 0.0092 0 0 0 0.028 0.0096 0 0 0 0.032 0.0102 0 0 0 0.037 0.0537 0 0 0 0.145 0.0621 0 0 0 0.186 0.0674 0 0 0 0.222 0.0728 0 0 0 0.262 3.869 0 0.0029 3.38 16.231 4.35 0 0.0031 3.6 19.536 4.8 0 0.0098 3.78 22.676 5.33 0 0.0145 9.4 53.080 19.6 0 0.003 3.6 59.081 22.1 0 0.004 3.9 73.327 23.8 0 0.012 3.9 85.600 26 0 0.02 9.9 129.312 7.8 0 0.003 3.5 27.050 8.9 0 0.004 3.8 33.547 9.6 0 0.012 3.8 38.560 10.5 0 0.014 9.5 72.050 4.77 0 0.23 3.7 19.599 5.4 0 0.25 3.9 23.670 6.04 0 0.46 3.9 28.470 6.6 0 0.49 10.1 61.884 5.1 1.4 0.0032 3.57 23.660 6.3 1.79 0.01 3.84 33.642 6.3 2.9 0.01 3.8 42.163 6.9 3.2 0.0132 9.8 58.054 5.1 240 0.0032 3.57 667.880 6.3 304 0.01 3.84 1030.935 6.3 450 0.01 3.8 2277.663 6.9 486 0.0132 9.8 2713.454 5.1 48 0.0032 3.57 149.480 6.3 56 0.01 3.84 212.535 6.3 82 0.01 3.8 437.663 6.9 90 0.0132 9.8 535.454 3 125 0.0034 3.63 351.813 3.77 154 0.0126 3.89 527.685 3.79 229 0.0126 3.7 1164.209 4.2 250 0.0163 9.7 1425.099
Off (Thermal sensor disabled, no clocks)
Sleep (Thermal sensor enabled, VMID enabled using 250k VMID resistors)
DAC Playback to 16Ohm headphones @44.1kHz, (no signal)
DAC Playback to 16Ohm headphones @44.1kHz, (white noise 1Vrms)
DAC Playback to 16Ohm headphones @44.1kHz, (1kHz tone 100mVrms)
DAC Playback to 16Ohm headphones @44.1kHz, PLL enabled, MCLK=12MHz, no signal, master mode DAC Playback to 8Ohm speakers @44.1kHz (no signal)
DAC Playback to 8Ohm speakers @44.1kHz (1kHz tone, full scale)
DAC Playback to 8Ohm speakers @44.1kHz (white noise, 1Vrms)
DAC Playback to mono speaker @44.1kHz (1kHz tone, full scale)
Note: 1. Power in the load is included.
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WM8956 SIGNAL TIMING REQUIREMENTS
SYSTEM CLOCK TIMING
Preliminary Technical Data
MCLK tMCLKY
Figure 2 System Clock Timing Requirements Test Conditions DCVDD=1.8V, DBVDD=AVDD=SPKVDD1=SPKVDD2=3.3V, DGND=AGND=SPKGND1=SPKGND2=0V, TA = +25oC PARAMETER System Clock Timing Information MCLK cycle time MCLK duty cycle TMCLKY TMCLKDS 33.33 60:40 40:60 ns SYMBOL CONDITIONS MIN TYP MAX UNIT
AUDIO INTERFACE TIMING - MASTER MODE
Figure 2 Digital Audio Data Timing - Master Mode (see Control Interface)
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Preliminary Technical Data
WM8956
Test Conditions DCVDD=1.8V, DBVDD=AVDD=SPKVDD1=SPKVDD2=3.3V, DGND=AGND=SPKGND1=SPKGND2=0V, TA=+25oC, Slave Mode, fs=48kHz, MCLK=256fs, 24-bit data, unless otherwise stated. PARAMETER Audio Data Input Timing Information DACLRC propagation delay from BCLK falling edge DACDAT setup time to BCLK rising edge DACDAT hold time from BCLK rising edge tDL tDST tDHT 10 10 10 ns ns ns SYMBOL MIN TYP MAX UNIT
AUDIO INTERFACE TIMING - SLAVE MODE
Figure 3 Digital Audio Data Timing - Slave Mode Test Conditions DCVDD=1.8V, DBVDD=AVDD=SPKVDD1=SPKVDD2=3.3V, DGND=AGND=SPKGND1=SPKGND2=0V, TA=+25oC, Slave Mode, fs=48kHz, MCLK= 256fs, 24-bit data, unless otherwise stated. PARAMETER Audio Data Input Timing Information BCLK cycle time BCLK pulse width high BCLK pulse width low DACLRC set-up time to BCLK rising edge DACLRC hold time from BCLK rising edge DACDAT hold time from BCLK rising edge DACDAT set-up time to BCLK rising edge Note: BCLK period should always be greater than or equal to MCLK period. tBCY tBCH tBCL tLRSU tLRH tDH tDS 50 20 20 10 10 10 10 ns ns ns ns ns ns ns SYMBOL MIN TYP MAX UNIT
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WM8956
CONTROL INTERFACE TIMING - 2-WIRE MODE
t3 SDIN t6 SCLK t1 t9 t7 t2 t5 t4 t3
Preliminary Technical Data
t8
Figure 4 Control Interface Timing - 2-Wire Serial Control Mode Test Conditions DCVDD=1.8V, DBVDD=AVDD=SPKVDD1=SPKVDD2=3.3V, DGND=AGND=SPKGND1=SPKGND2=0V, TA=+25oC, Slave Mode, fs=48kHz, MCLK = 256fs, 24-bit data, unless otherwise stated. PARAMETER Program Register Input Information SCLK Frequency SCLK Low Pulse-Width SCLK High Pulse-Width Hold Time (Start Condition) Setup Time (Start Condition) Data Setup Time SDIN, SCLK Rise Time SDIN, SCLK Fall Time Setup Time (Stop Condition) Data Hold Time Pulse width of spikes that will be suppressed t1 t2 t3 t4 t5 t6 t7 t8 t9 tps 0 600 900 5 1.3 600 600 600 100 300 300 526 kHz us ns ns ns ns ns ns ns ns ns SYMBOL MIN TYP MAX UNIT
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Preliminary Technical Data
WM8956
INTERNAL POWER ON RESET CIRCUIT
Figure 5 Internal Power on Reset Circuit Schematic The WM8956 includes an internal Power-On-Reset Circuit, as shown in Figure 5, which is used to reset the digital logic into a default state after power up. The POR circuit is powered from AVDD and monitors DCVDD. It asserts PORB low if AVDD or DCVDD is below a minimum threshold.
Figure 6 Typical Power up Sequence where AVDD is Powered before DCVDD Figure 6 shows a typical power-up sequence where AVDD comes up first. When AVDD goes above the minimum threshold, Vpora, there is enough voltage for the circuit to guarantee PORB is asserted low and the chip is held in reset. In this condition, all writes to the control interface are ignored. Now AVDD is at full supply level. Next DCVDD rises to Vpord_on and PORB is released high and all registers are in their default state and writes to the control interface may take place. On power down, where AVDD falls first, PORB is asserted low whenever AVDD drops below the minimum threshold Vpora_off.
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WM8956
Preliminary Technical Data
Figure 7 Typical Power up Sequence where DCVDD is Powered before AVDD Figure 7 shows a typical power-up sequence where DCVDD comes up first. First it is assumed that DCVDD is already up to specified operating voltage. When AVDD goes above the minimum threshold, Vpora, there is enough voltage for the circuit to guarantee PORB is asserted low and the chip is held in reset. In this condition, all writes to the control interface are ignored. When AVDD rises to Vpora_on, PORB is released high and all registers are in their default state and writes to the control interface may take place. On power down, where DCVDD falls first, PORB is asserted low whenever DCVDD drops below the minimum threshold Vpord_off.
SYMBOL Vpora Vpora_on Vpora_off Vpord_on Vpord_off
MIN 0.4 0.9 0.4 0.5 0.4
TYP 0.6 1.2 0.6 0.7 0.6
MAX 0.8 1.6 0.8 0.9 0.8
UNIT V V V V V
Table 1 Typical POR Operation (typical values, not tested) Notes: 1. If AVDD and DCVDD suffer a brown-out (i.e. drop below the minimum recommended operating level but do not go below Vpora_off or Vpord_off) then the chip will not reset and will resume normal operation when the voltage is back to the recommended level again. The chip will enter reset at power down when AVDD or DCVDD falls below Vpora_off or Vpord_off. This may be important if the supply is turned on and off frequently by a power management system. The minimum tpor period is maintained even if DCVDD and AVDD have zero rise time. This specification is guaranteed by design rather than test.
2.
3.
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Preliminary Technical Data
WM8956
DEVICE DESCRIPTION
INTRODUCTION
The WM8956 is a low power audio DAC offering a combination of high quality audio, advanced features, low power and small size. These characteristics make it ideal for portable digital audio applications with stereo speaker and headphone outputs such as games consoles, portable media players and multimedia phones. Stereo class D speaker drivers can provide 1W per channel into 8 loads. BTL configuration provides high power output and excellent PSRR. Low leakage and pop/click suppression mechanisms allow direct battery connection, reducing component count and power consumption in portable battery-powered applications. Highly flexible speaker boost settings provide fully internal level-shifting of analogue output signals, allowing speaker output power to be maximised while minimising other analogue supply currents, and requiring no additional components. A flexible input configuration includes support for two stereo microphone interfaces (single-ended or pseudo-differential) and additional stereo line inputs. Up to three stereo analogue input sources are available, removing the need for external analogue switches in many applications. Boost amplifiers are available for additional gain on the microphone inputs. The stereo DACs are of hi-fi quality using a 24-bit, low-order oversampling architecture to deliver optimum performance. The DAC output signal can be mixed with analogue input signals from the line inputs or bypass paths. This mix is available on speaker and headphone/line outputs. The WM8956 has a configurable digital audio interface where digital audio playback data is fed to the DAC. It supports a number of audio data formats including I2S, DSP Mode (a burst mode in which frame sync plus two data packed words are transmitted), MSB-First, left justified and MSB-First, right justified, and can operate in master or slave modes. In PCM mode A-law and -law companding is supported. The SYSCLK (system clock) provides clocking for the DACs, DSP core, class D outputs and the digital audio interface. SYSCLK can be derived directly from the MCLK pin or via an integrated PLL, providing flexibility to support a wide range of clocking schemes. All MCLK frequencies typically used in portable systems are supported for sample rates between 8kHz and 48kHz. A flexible switching clock for the class D speaker drivers (synchronous with the audio DSP clocks for best performance) is also derived from SYSCLK. To allow full software control over all its features, the WM8956 uses a 2 wire control interface. It is fully compatible and an ideal partner for a wide range of industry standard microprocessors, controllers and DSPs. Unused circuitry can be disabled via software to save power, while low leakage currents extend standby and off time in portable battery-powered applications.
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WM8956
INPUT SIGNAL PATH
Preliminary Technical Data
The WM8956 has three flexible stereo analogue input channels which can be configured as line inputs, differential microphone inputs or single-ended microphone inputs. Line inputs and microphone PGA outputs can be routed directly to the output mixers via a bypass path.
MICROPHONE INPUTS
Differential microphones can be connected between LINPUT1 and LINPUT2 or LINPUT3, and between RINPUT1 and RINPUT2 or RINPUT3. Alternatively single-ended microphones can be connected to LINPUT1 or RINPUT1. In single-ended microphone input configuration the microphone signal should be input to LINPUT1 or RINPUT1 and the internal non-inverting input of the input PGA should be switched to VMID. In differential mode the larger signal should be input to LINPUT2 or LINPUT3 on the left channel, or RINPUT2 or RINPUT3 on the right channel. The smaller (e.g. noisy ground connection) should be input to LINPUT1 or RINPUT1. The gain of the microphone PGAs is controlled directly via software. The inputs LINPUT2, RINPUT2, LINPUT3 and RINPUT3 should not be connected to the boost mixer or bypass path while operating as the non-inverting input in differential microphone configuration.
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Preliminary Technical Data
WM8956
Figure 8 Analogue Left Input Equivalent Circuit
Figure 9 Analogue Right Input Equivalent Circuit
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WM8956
Preliminary Technical Data The input PGAs and boost mixers are enabled by the AINL and AINR register bits. The microphone PGAs can be also be disabled independently of the boost mixer to save power, using LMIC and RMIC register bits. REGISTER ADDRESS R25 (19h) Power Management (1) 5 BIT LABEL AINL DEFAULT 0 DESCRIPTION Left channel input PGA and boost stage enable 0 = PGA disabled, boost disabled 1 = PGA enabled (if LMIC = 1), boost enabled Right channel input PGA and boost stage enable 0 = PGA disabled, boost disabled 1 = PGA enabled (if LMIC = 1), boost enabled Left channel input PGA enable 0 = PGA disabled 1 = PGA enabled (if AINL = 1) Right channel input PGA enable 0 = PGA disabled 1 = PGA enabled (if AINR = 1)
4
AINR
0
R47 (2Fh) Power Management (3)
5
LMIC
0
4
RMIC
0
Table 2 Input PGA and Boost Enable Register Settings The input PGAs can be configured as differential inputs, using LINPUT1/LINPUT2 or LINPUT1/LINPUT3, and RINPUT1/RINPUT2 or RINPUT1/RINPUT3. The input impedance to these non-inverting inputs is constant in this configuration. Differential configuration is controlled by LMP2, LMP3, RMP2 and RMP3 as shown in Table 3. When single-ended configuration is selected, the non-inverting input of the PGA is connected to VMID. REGISTER ADDRESS R32 (20h) Left Input Signal Path BIT 3 LABEL LMIC2B DEFAULT 0 DESCRIPTION Connect Left Input PGA to Left Input Boost mixer 0 = Not connected 1 = Connected Connect LINPUT2 to non-inverting input of Left Input PGA 0 = LINPUT2 not connected to PGA 1 = LINPUT2 connected to PGA (Constant input impedance) Connect LINPUT3 to non-inverting input of Left Input PGA 0 = LINPUT3 not connected to PGA 1 = LINPUT3 connected to PGA (Constant input impedance) Connect LINPUT1 to inverting input of Left Input PGA 0 = LINPUT1 not connected to PGA 1 = LINPUT1 connected to PGA Connect Right Input PGA to Right Input Boost mixer 0 = Not connected 1 = Connected Connect RINPUT2 to non-inverting input of Right Input PGA 0 = RINPUT2 not connected to PGA 1 = RINPUT2 connected to PGA (Constant input impedance)
6
LMP2
0
7
LMP3
0
8
LMN1
1
R33 (21h) Right Input Signal Path
3
RMIC2B
0
6
RMP2
0
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Preliminary Technical Data 7 RMP3 0
WM8956
Connect RINPUT3 to non-inverting input of Right Input PGA 0 = RINPUT3 not connected to PGA 1 = RINPUT3 connected to PGA (Constant input impedance) Connect RINPUT1 to inverting input of Right Input PGA 0 = RINPUT1 not connected to PGA 1 = RINPUT1 connected to PGA
8
RMN1
1
Table 3 Input PGA Control
INPUT PGA VOLUME CONTROLS
The input PGAs have a gain range from -17.25dB to +30dB in 0.75dB steps. The gains from the inverting inputs (LINPUT1 and RINPUT1) to the PGA outputs and from the non-inverting inputs (LINPUT2/RINPUT2 and LINPUT3/RINPUT3) to the PGA output are always common in differential configuration and controlled by the register bits LINVOL[5:0] and RINVOL[5:0]. The left and right input PGAs can be independently muted using the LINMUTE and RINMUTE register bits. To allow simultaneous volume updates of left and right channels, PGA gains are not altered until a 1 is written to the IPVU bit. To prevent "zipper noise", a zero-cross function is provided, so that when enabled, volume updates will not take place until a zero-crossing is detected. In the event of a long period without zerocrossings, a timeout function is available. When this function is enabled (using the TOEN register bit), the volume will update automatically after a timeout. The timeout period is set by TOCLKSEL. Note that an MCLK must be input to the device and SYSCLK running internally to use the timeout function.
REGISTER ADDRESS R0 (00h) Left Channel PGA 8
BIT
LABEL IPVU
DEFAULT 0
DESCRIPTION Input PGA Volume Update 0 = Store LINVOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = LINVOL, right = intermediate latch) Left Input PGA Analogue Mute 1 = Enable Mute 0 = Disable Mute Note: IPVU must be set to un-mute. Left Input PGA Zero Cross Detector 1 = Change gain on zero cross only 0 = Change gain immediately Left Input PGA Volume Control 111111 = +30dB 111110 = +29.25dB . . 0.75dB steps down to 000000 = -17.25dB Input PGA Volume Update 0 = Store RINVOL in intermediate latch (no gain change) 1 = Update left and right channel gains (right = RINVOL, left = intermediate latch)
7
LINMUTE
1
6
LIZC
0
5:0
LINVOL [5:0]
010111 ( 0dB )
R1 (01h) Right Channel PGA
8
IPVU
0
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WM8956
7 RINMUTE 1
Preliminary Technical Data Right Input PGA Analogue Mute 1 = Enable Mute 0 = Disable Mute Note: IPVU must be set to un-mute. Right Input PGA Zero Cross Detector 1 = Change gain on zero cross only 0 = Change gain immediately Right Input PGA Volume Control 111111 = +30dB 111110 = +29.25dB . . 0.75dB steps down to 000000 = -17.25dB Timeout Enable (Also enables jack detect debounce clock) 0 = Timeout disabled 1 = Timeout enabled Slow Clock Selection (Used for volume update timeouts and for jack detect debounce) 0 = SYSCLK / 221 (Slower Response) 1 = SYSCLK / 219 (Faster Response)
6
RIZC
0
5:0
RINVOL [5:0]
010111 ( 0dB )
R23 (17h) Additional Control (1)
0
TOEN
0
1
TOCLKSEL
0
Table 4 Input PGA Volume Control See "Volume Updates" for more information on volume update bits, zero cross and timeout operation.
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Preliminary Technical Data
WM8956
LINE INPUTS
Two pairs of stereo line inputs (LINPUT2 / RINPUT2 and LINPUT3 / RINPUT3) are available as analogue inputs into the output mixers via the bypass paths. See "Output Signal Path" for more information on the bypass paths.
INPUT BOOST
The boost stage in the input path can mix signals from the microphone PGAs and the line inputs. The boost stage can provide up to +29dB additional gain from the microphone PGA output, providing a total maximum available analogue gain of +59dB from microphone to output mixers. The microphone PGA path to the boost mixer is muted using LINMUTE and RINMUTE as shown in Table 4. Microphone PGA to boost gain settings are shown in Table 5. REGISTER ADDRESS R32 (20h) Left Input Signal Path BIT 5:4 LABEL LMICBOOST [1:0] DEFAULT 00 DESCRIPTION Left Channel Input PGA Boost Gain 00 = +0dB 01 = +13dB 10 = +20dB 11 = +29dB Right Channel Input PGA Boost Gain 00 = +0dB 01 = +13dB 10 = +20dB 11 = +29dB
R33 (21h) Right Input Signal Path
5:4
RMICBOOST [1:0]
00
Table 5 Microphone PGA Boost Control For line inputs, -12dB to +6dB gain is available on the boost mixer, with mute control, as shown in Table 6. REGISTER ADDRESS R43 (2Bh) Input Boost Mixer 1 BIT 6:4 LABEL LIN3BOOST [2:0] DEFAULT 000 DESCRIPTION LINPUT3 to Boost Mixer gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB LINPUT2 to Boost Mixer gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB RINPUT3 to Boost Mixer gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB RINPUT2 to Boost Mixer gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB
3:1
LIN2BOOST [2:0]
000
R44 (2Ch) Input Boost Mixer 2
6:4
RIN3BOOST [2:0]
000
3:1
RIN2BOOST [2:0]
000
Table 6 Line Input Boost Control When all three input paths to the boost mixer are disabled, the boost mixer will automatically be muted.
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WM8956
MICROPHONE BIASING CIRCUIT
Preliminary Technical Data
The MICBIAS output provides a low noise reference voltage suitable for biasing electret type microphones and the associated external resistor biasing network. Refer to the Applications Information section for recommended external components. The MICBIAS voltage can be altered via the MBSEL register bit. When MBSEL=0, MICBIAS=0.9*AVDD and when MBSEL=1, MICBIAS=0.65*AVDD. The output can be enabled or disabled using the MICB control bit. REGISTER ADDRESS R25 (19h) Power management (1) R48 (30h) Additional Control (4) BIT 1 LABEL MICB DEFAULT 0 DESCRIPTION Microphone Bias Enable 0 = OFF (high impedance output) 1 = ON Microphone Bias Voltage Control 0 = 0.9 * AVDD 1 = 0.65 * AVDD
0
MBSEL
0
Table 7 Microphone Bias Control The internal MICBIAS circuitry is shown in Figure 10. The maximum source current capability for MICBIAS is 3mA. The external biasing resistors therefore must be large enough to limit the MICBIAS current to 3mA.
Figure 10 Microphone Bias Schematic
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Preliminary Technical Data
WM8956
EXAMPLE INPUT CONFIGURATIONS
Some example input configurations are shown below. Single-ended MIC configuration on left channel. LINPUT2 and LINPUT3 unused
Pseudo-differential MIC configuration on left channel using LINPUT1 as ground connection and LINPUT2 as signal input. LINPUT3 unused.
Single-ended MIC configuration on left channel. LINPUT2 used as additional input to boost stage. LINPUT3 unused.
Single-ended MIC configuration on left channel. LINPUT3 used as input to bypass path. LINPUT2 unused.
Figure 11 Example Microphone Input Configurations (See also "Recommended External Components")
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WM8956
OUTPUT SIGNAL PATH
Preliminary Technical Data
The hi-fi DACs and DAC digital filters are enabled by register bits DACL and DACR. The mixers and output drivers can be separately enabled by individual control bits (see Analogue Outputs). Thus it is possible to utilise the analogue mixing and amplification provided by the WM8956, irrespective of whether the DACs are enabled or not. The WM8956 DACs receive digital input data on the DACDAT pin. The digital filter block processes the data to provide the following functions: Digital volume control with soft mute and soft un-mute Mono mix 3D stereo enhancement De-emphasis Sigma-delta modulation High performance sigma-delta 24-bit audio DAC converts the digital data into an analogue signal. The analogue outputs from the DACs can then be mixed with the analogue line inputs. This mix is fed to the output drivers for headphone or speaker output. OUT3 can provide a mono mix of left and right mixers or a pseudo-ground for capless headphone drive.
DIGITAL PLAYBACK (DAC) PATH
Digital data is passed to the WM8956 via the flexible audio interface to the hi-fi DACs. The DACs are enabled by the DACL and DACR register bits. REGISTER ADDRESS R26 (1Ah) Power Management (2) BIT 8 LABEL DACL DEFAULT 0 DESCRIPTION Left Channel DAC Enable 0 = DAC disabled 1 = DAC enabled Right Channel DAC Enable 0 = DAC disabled 1 = DAC enabled
7
DACR
0
Table 8 DAC Enable Control
DIGITAL DAC VOLUME CONTROL
The signal volume from each DAC can be controlled digitally. The gain and attenuation range is - 127dB to 0dB in 0.5dB steps. The level of attenuation for an eight-bit code X is given by: 0.5 x (X-255) dB for 1 X 255; MUTE for X = 0
The DACVU control bit controls the loading of digital volume control data. When DACVU is set to 0, the LDACVOL or RDACVOL control data is loaded into an intermediate register, but the actual gain does not change. Both left and right gain settings are updated simultaneously when DACVU is set to 1. See "Volume Updates" for more information on volume update bits.
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Preliminary Technical Data
WM8956
REGISTER ADDRESS R10 (0Ah) Left Channel Digital Volume BIT 8 LABEL DACVU DEFAULT 0 DESCRIPTION DAC Volume Update 0 = Store LDACVOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = LDACVOL, right = intermediate latch) Left DAC Digital Volume Control 0000 0000 = Digital Mute 0000 0001 = -127dB 0000 0010 = -126.5dB ... 0.5dB steps up to 1111 1111 = 0dB DAC Volume Update 0 = Store RDACVOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = intermediate latch, right = RDACVOL) Right DAC Digital Volume Control similar to LDACVOL
7:0
LDACVOL [7:0]
11111111 ( 0dB )
R11 (0Bh) Right Channel Digital Volume
8
DACVU
0
7:0
RDACVOL [7:0]
11111111 ( 0dB )
Table 9 Digital Volume Control
DAC SOFT MUTE AND SOFT UN-MUTE
The WM8956 also has a soft mute function, which, when enabled, gradually attenuates the volume of the digital signal to zero. When soft mute is disabled, the gain will either gradually ramp back up to the digital gain setting, or return instantly to the digital gain setting, depending on the DACSMM register bit. The DAC is soft-muted by default. To play back an audio signal, this function must first be disabled by setting the DACMU bit to zero. DACSMM would typically be enabled when using soft mute during playback of audio data so that when soft mute is then disabled, the sudden volume increase will not create pop noise by jumping immediately to the previous volume level (e.g. resuming playback after pausing during a track). DACSMM would typically be disabled when un-muting at the start of a digital music file, so that the first part of the track is not attenuated (e.g. when starting playback of a new track, or resuming playback after pausing between tracks). DAC muting and un-muting using volume control bits LDACVOL and RDACVOL.
DAC muting and un-muting using soft mute bit DACMU. Soft un-mute not enabled (DACSMM = 0).
DAC muting and un-muting using soft mute bit DACMU. Soft un-mute enabled (DACSMM = 1).
Figure 12 DAC Mute Control The volume ramp rate during soft mute and un-mute is controlled by the DACMR bit. Ramp rates of fs/32 and fs/2 are selectable as shown in Table 10 (fs = DAC sample rate).
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WM8956
REGISTER ADDRESS R5 (05h) DAC Control (1) R6 (06h) DAC Control (2) BIT 3 LABEL DACMU DEFAULT 1
Preliminary Technical Data DESCRIPTION Digital Soft Mute 1 = Mute 0 = No mute (signal active) DAC Soft Mute Mode 0 = Disabling soft-mute (DACMU=0) will cause the volume to change immediately to the LDACVOL / RDACVOL settings 1 = Disabling soft-mute (DACMU=0) will cause the volume to ramp up gradually to the LDACVOL / RDACVOL settings DAC Soft Mute Ramp Rate 0 = Fast ramp (fs/2, providing maximum delay of 10.7ms at fs=48k) 1 = Slow ramp (fs/32, providing maximum delay of 171ms at fs=48k)
3
DACSMM
0
2
DACMR
0
Table 10 DAC Soft-Mute Control
DAC DE-EMPHASIS
Digital de-emphasis can be applied to the DAC playback data (e.g. when the data comes from a CD with pre-emphasis used in the recording). De-emphasis filtering is available for sample rates of 48kHz, 44.1kHz and 32kHz. REGISTER ADDRESS R5 (05h) DAC Control (1) BIT 2:1 LABEL DEEMPH [1:0] DEFAULT 00 DESCRIPTION De-Emphasis Control 11 = 48kHz sample rate 10 = 44.1kHz sample rate 01 = 32kHz sample rate 00 = No de-emphasis
Table 11 DAC De-Emphasis Control
DAC OUTPUT PHASE AND MONO MIXING
The digital audio data is converted to oversampled bit streams in the on-chip, true 24-bit digital interpolation filters. The bitstream data enters two multi-bit, sigma-delta DACs, which convert them to high quality analogue audio signals. The multi-bit DAC architecture reduces high frequency noise and sensitivity to clock jitter. It also uses a Dynamic Element Matching technique for high linearity and low distortion. In normal operation, the left and right channel digital audio data is converted to analogue in two separate DACs. There is a mono-mix mode where the two audio channels are mixed together digitally and then converted to analogue using only one DAC, while the other DAC is switched off. The mono-mix signal can be selected to appear on both analogue output channels. The mono mix is automatically attenuated by 6dB to prevent clipping. The DAC output defaults to non-inverted. Setting DACPOL[0] bit will invert the left DAC output phase and setting DACPOL[1] bit will invert the right DAC output phase.
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Preliminary Technical Data
WM8956
REGISTER ADDRESS R6 (06h) DAC Control (2) BIT 6:5 LABEL DACPOL[1:0] DEFAULT 00 DESCRIPTION DAC Polarity Control: 00 = Polarity not inverted 01 = DAC L inverted 10 = DAC R inverted 11 = DAC L and R inverted DAC Mono Mix 0 = Stereo 1 = Mono (Mono MIX output on enabled DACs)
R23 (17h) Additional Control (1)
4
DMONOMIX
0
Table 12 DAC Mono Mix and Phase Invert Select
3D STEREO ENHANCEMENT
The WM8956 has a digital 3D enhancement option to artificially increase the separation between the left and right channels. This effect can only be used for playback, not for record. The 3D enhancement function is activated by the 3DEN bit, and the 3DDEPTH setting controls the degree of stereo expansion. Additionally, one of four filter characteristics can be selected for the 3D processing, using the 3DUC and 3DLC control bits. REGISTER ADDRESS R16 (10h) 3D enhance 6 BIT 3DUC LABEL DEFAULT 0 DESCRIPTION Upper Cut-Off Frequency 0 = High (Recommended for fs>=32kHz) 1 = Low (Recommended for fs<32kHz) Lower Cut-Off Frequency 0 = Low (Recommended for fs>=32kHz) 1 = High (Recommended for fs<32kHz) 3D Stereo Depth 0000 = 0% (minimum 3D effect) 0001 = 6.67% .... 1110 = 93.3% 1111 = 100% (maximum 3D effect) 3D Stereo Enhancement Enable 0 = Disabled 1 = Enabled
5
3DLC
0
4:1
3DDEPTH [3:0]
0000
0
3DEN
0
Table 13 3D Stereo Enhancement Function When 3D enhancement is enabled it may be necessary to attenuate the signal by 6dB to avoid limiting. This is a user-selectable function, enabled by setting DACDIV2. REGISTER ADDRESS R5 (05h) DAC control (1) 7 BIT LABEL DACDIV2 DEFAULT 0 DESCRIPTION DAC 6dB attenuate enable 0 = disabled (0dB) 1 = -6dB enabled
Table 14 DAC 6dB Attenuation Select
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WM8956
OUTPUT MIXERS
Preliminary Technical Data
Left and right analogue mixers allow the DAC output and analogue bypass paths to be mixed. Programmable attenuation and mute is available on the analogue bypass paths from LINPUT3, RINPUT3 and from the input boost mixers as shown in Figure 13. A mono mix of left and right output mixers is also available on OUT3.
Figure 13 Output Mixer Path Left and right mixers are enabled by the LOMIX and ROMIX register bits. The mono mixer is enabled by OUT3 register bit, which also enables the OUT3 driver. REGISTER ADDRESS R47 (2Fh) Power Management (3) 3 BIT LABEL LOMIX DEFAULT 0 DESCRIPTION Left Output Mixer Enable Control 0 = Disabled 1 = Enabled Right Output Mixer Enable Control 0 = Disabled 1 = Enabled Mono Output and Mono Mixer Enable Control 0 = Mono mixer and output disabled 1 = Mono mixer and output enabled
4
ROMIX
0
R26 (1Ah) Power Management (2)
1
OUT3
0
Table 15 Output Mixer Enable Control Inputs to the mixers from the DAC and bypass paths can be individually muted. The bypass paths have programmable attenuation as shown in Table 16. To prevent pop noise, it is recommended not to change volume levels of these paths during playback.
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Preliminary Technical Data
WM8956
REGISTER ADDRESS R34 (22h) Left Output Mixer Control BIT 8 LABEL LD2LO DEFAULT 0 DESCRIPTION Left DAC to Left Output Mixer 0 = Disable (Mute) 1 = Enable Path LINPUT3 to Left Output Mixer 0 = Disable (Mute) 1 = Enable Path LINPUT3 to Left Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Left Input Boost Mixer to Left Output Mixer 0 = Disable (Mute) 1 = Enable Path Left Input Boost Mixer to Left Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Right DAC to Right Output Mixer 0 = Disable (Mute) 1 = Enable Path RINPUT3 to Right Output Mixer 0 = Disable (Mute) 1 = Enable Path RINPUT3 to Right Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Right Input Boost Mixer to Right Output Mixer 0 = Disable (Mute) 1 = Enable Path Right Input Boost Mixer to Right Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB
7
LI2LO
0
6:4
LI2LOVOL [2:0]
101 (-15dB)
R45 (2Dh) Bypass (1)
7
LB2LO
0
6:4
LB2LOVOL [2:0]
101 (-15dB)
R37 (25h) Right Output Mixer Control
8
RD2RO
0
7
RI2RO
0
6:4
RI2ROVOL [2:0]
101 (-15dB)
R46 (2Eh) Bypass (2)
7
RB2RO
0
6:4
RB2ROVOL [2:0]
101 (-15dB)
Table 16 Left and Right Output Mixer Mute and Volume Control The mono output mixer can output, left, right, left+right or a buffered VMID. 0dB or 6dB attenuation is selectable using MOUTVOL register bit. It is recommended to attenuate a mono mix of left and right channels by 6dB in order to prevent clipping. This attenuation control (MOUTVOL) should not be modified while OUT3 is enabled as this may cause an audible click noise.
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WM8956
REGISTER ADDRESS R38 (26h) Mono Out Mix (1) R39 (27h) Mono Out Mix (2) R42 (2Ah) Mono Out Volume BIT 7 LABEL L2MO DEFAULT 0
Preliminary Technical Data
DESCRIPTION Left Output Mixer to Mono Output Mixer Control 0 = Left channel mix disabled 1 = Left channel mix enabled Right Output Mixer to Mono Output Mixer Control 0 = Right channel mix disabled 1 = Right channel mix enabled Mono Output Mixer Volume Control 0 = 0dB 1 = -6dB
7
R2MO
0
6
MOUTVOL
1
Table 17 Output Mixer Enable Control When left and right inputs to the mono mixer are both disabled, the mono mixer will output VMID.
ANALOGUE OUTPUTS
HP_L AND HP_R OUTPUTS
The HP_L and HP_R pins can drive a 16 or 32 headphone or a line output (see Headphone Output and Line Output sections, respectively). The signal volume on HP_L and HP_R can be independently adjusted under software control by writing to LOUT1VOL and ROUT1VOL, respectively. Note that gains over 0dB may cause clipping if the signal is large. Any gain setting below 0101111 (minimum) mutes the output driver. The corresponding output pin remains at the same DC level (the reference voltage on the VREF pin), so that no click noise is produced when muting or un-muting. A zero cross detect on the analogue output may also be enabled when changing the gain setting to minimize audible clicks and zipper noise as the gain updates. If zero cross is enabled a timeout is also available to update the gain if a zero cross does not occur. This function may be enabled by setting TOEN in register R23 (17h). The timeout period is set by TOCLKSEL. Note that SYSCLK must be enabled to use this function.
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Preliminary Technical Data
WM8956
REGISTER ADDRESS R2 (02h) LOUT1 Volume BIT 8 LABEL OUT1VU DEFAULT 0 DESCRIPTION Headphone Volume Update 0 = Store LOUT1VOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = LOUT1VOL, right = intermediate latch) Left zero cross enable 0 = Change gain immediately 1 = Change gain on zero cross only LOUT1 Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Headphone Volume Update 0 = Store ROUT1VOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = intermediate latch, right = ROUT1VOL) Right zero cross enable 0 = Change gain immediately 1 = Change gain on zero cross only ROUT1 Volume Similar to LOUT1VOL
7
LO1ZC
0
6:0
LOUT1VOL [6:0]
0000000 (MUTE)
R3 (03h) ROUT1 Volume
8
OUT1VU
0
7
RO1ZC
0
6:0
ROUT1VOL [6:0]
0000000 (MUTE)
Table 18 LOUT1/ROUT1 Volume Control See "Volume Updates" for more information on volume update bits, zero cross and timeout operation.
CLASS D SPEAKER OUTPUTS
The SPK_LP/SPK_LN and SPK_RP/SPK_RN output pins are class D speaker drivers. Each pair is independently controlled and can drive an 8 BTL speaker (see Speaker Output section). Output mixer volume is relative to AVDD, while an additional boost stage is available to accommodate higher SPKVDD1/SPKVDD2 supply voltages. This allows AVDD to be run at a lower voltage to save power, while maximum output power can be delivered to the load, utilising the full range of SPKVDD1/SPKVDD2. Note that the BTL speaker connection provides an additional +6dB gain at the output.
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Preliminary Technical Data
Figure 14 Speaker Boost Operation
REGISTER ADDRESS R40 (28h) Left Speaker Volume
BIT 6:0
LABEL SPKLVOL [6:0]
DEFAULT 0000000 (MUTE)
DESCRIPTION SPK_LP/SPK_LN Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Left Speaker Zero Cross Enable 1 = Change gain on zero cross only 0 = Change gain immediately Speaker Volume Update 0 = Store SPKLVOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = SPKLVOL, right = intermediate latch) SPK_RP/SPK_RN Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Right Speaker Zero Cross Enable 1 = Change gain on zero cross only 0 = Change gain immediately Speaker Volume Update 0 = Store SPKRVOL in intermediate latch (no gain change) 1 = Update left and right channel gains (left = intermediate latch, right = SPKRVOL) DC Speaker Boost (Boosts speaker DC output level by up to 1.8 x on left and right channels) 000 = 1.00x boost (+0dB) 001 = 1.27x boost (+2.1dB) 010 = 1.40x boost (+2.9dB) 011 = 1.52x boost (+3.6dB) 100 = 1.67x boost (+4.5dB) 101 = 1.8x boost (+5.1dB) 110 to 111 = Reserved PTD, July 2007, Rev 2.1 34
7
SPKLZC
0
8
SPKVU
0
R41 (29h) Right Speaker Volume
6:0
SPKRVOL [6:0]
0000000 (MUTE)
7
SPKRZC
0
8
SPKVU
0
R51 (33h) Class D Control (3)
5:3
DCGAIN [2:0]
000 (1.0x)
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Preliminary Technical Data REGISTER ADDRESS BIT 2:0 LABEL ACGAIN [2:0] DEFAULT 000 (1.0x)
WM8956
DESCRIPTION AC Speaker Boost (Boosts speaker AC output signal by up to 1.8 x on left and right channels) 000 = 1.00x boost (+0dB) 001 = 1.27x boost (+2.1dB) 010 = 1.40x boost (+2.9dB) 011 = 1.52x boost (+3.6dB) 100 = 1.67x boost (+4.5dB) 101 = 1.8x boost (+5.1dB) 110 to 111 = Reserved
Table 19 SPK_L/SPK_R Volume and Speaker Boost Control To prevent pop noise, DCGAIN and ACGAIN should not be modified while the speaker outputs are enabled. To avoid clipping at speaker ground, ACGAIN should not be greater than DCGAIN. To avoid clipping at speaker supply, SPKVDD1 and SPKVDD2 must be high enough to support the peak output voltage when using DCGAIN and ACGAIN functions. The peak output voltage is AVDD*(DCGAIN+ACGAIN)/2. DCGAIN should normally be set to the same value as ACGAIN. See "Volume Updates" for more information on volume update bits, zero cross and timeout operation. See "Class D Speaker Outputs" for more information on class D speaker operation.
OUT3 OUTPUT
The OUT3 pin can drive a 16 or 32 headphone or a line output or be used as a pseudo-ground for capless headphone drive (see Headphone Output section). It can also drive out a mono mix of left and right output mixers (See Output Signal Path).
ENABLING THE OUTPUTS
Each analogue output of the WM8956 can be independently enabled or disabled. The analogue mixer associated with each output is powered on or off along with the output pin. All outputs are disabled by default. To save power, unused outputs should remain disabled.
REGISTER ADDRESS R26 (1Ah) Power Management (2)
BIT 6 5 4 3 1
LABEL LOUT1 ROUT1 SPKL SPKR OUT3 SPK_OP_EN [1:0]
DEFAULT 0 0 0 0 0 00
DESCRIPTION LOUT1 Output Enable ROUT1 Output Enable SPK_LP and SPK_LN Volume Control Enable SPK_RP and SPK_RN Volume Control Enable OUT3 Enable Enable Class D Speaker Outputs 00 = Off 01 = Left speaker only 10 = Right speaker only 11 = Left and right speakers enabled
R49 (31h) Class D Control (1)
7:6
Note: All "Enable" bits are 1 = ON, 0 = OFF Table 20 Analogue Output Control
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Preliminary Technical Data The speaker output enable bits SPK_OP_EN[1:0] should not be enabled until there is a valid switching clock to drive the class D outputs. This means that SYSCLK must be active, and DCLKDIV set to an appropriate value to produce a class D clock of between 700kHz and 800kHz for best performance (See "Class D Speaker Outputs" and "Clocking and Sample Rates" sections for more information). Whenever an analogue output is disabled, it remains connected to VREF through a resistor. This helps to prevent pop noise when the output is re-enabled. The resistance between VREF and each output can be controlled using the VROI bit in register 27. If a high impedance is desired for disabled outputs, VROI can then be set to 1, increasing the resistance to about 20k. REGISTER ADDRESS R27 (1Bh) Additional (1) BIT 6 LABEL VROI 0 DEFAULT DESCRIPTION VREF to Analogue Output Resistance (Disabled Outputs) 0 = 500 VMID to output 1 = 20k VMID to output
Table 21 Disabled Outputs to VREF Resistance
HEADPHONE OUTPUT
Analogue outputs HP_L/HP_R, and OUT3, can drive a 16 or 32 headphone load, either through DC blocking capacitors, or DC coupled without any capacitor. Headphone Output using DC blocking capacitors DC Coupled Headphone Output (L2MO=0; R2MO=0)
Figure 15 Recommended Headphone Output Configurations When DC blocking capacitors are used, then their capacitance and the load resistance together determine the lower cut-off frequency, fc. Increasing the capacitance lowers fc, improving the bass response. Smaller capacitance values will diminish the bass response. Assuming a 32 load and C1, C2 = 100F: fc = 1 / 2 RLC1 = 1 / (2 x 32 x 100F) = 50 Hz In the DC coupled configuration, the headphone "ground" is connected to the OUT3 pin, which must be enabled by setting OUT3 = 1 and muted by setting L2MO=0 and R2MO=0. As the OUT3 pin produces a DC voltage of AVDD/2 (=VREF), there is no DC offset between HP_L/HP_R and OUT3, and therefore no DC blocking capacitors are required. This saves space and material cost in portable applications. It is recommended to connect the DC coupled headphone outputs only to headphones, and not to the line input of another device. Although the built-in short circuit protection will prevent any damage to the headphone outputs, such a connection may be noisy, and may not function properly if the other device is grounded.
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Preliminary Technical Data
WM8956
CLASS D SPEAKER OUTPUTS
The class D speaker outputs SPK_LN/SPK_LP and SPK_RN/SPK_RP can drive 1W into 8 BTL speakers. Class D outputs reduce power consumption and maximise efficiency by reducing power dissipated in the output drivers, delivering most of the power directly to the load. This is achieved by pulse width modulation (PWM) of a high frequency square wave, allowing the audio signal level to be set by controlling the pulse width. The frequency of the output waveform is controlled by DCLKDIV, and is derived from SYSCLK. When the speakers are close to the device (typically less than about 100mm) the internal filtering effects of the speaker can be used. Where signals are routed over longer distances, it is recommended to use additional passive filtering, positioned close to the WM8956, to reduce EMI. See "Applications Information" for more information on EMI reduction. REGISTER ADDRESS R8 (08h) Clocking (2) BIT 8:6 LABEL DCLKDIV DEFAULT 111 DESCRIPTION Controls clock division from SYSCLK to generate suitable class D clock. 000 = SYSCLK / 1.5 001 = SYSCLK / 2 010 = SYSCLK / 3 011 = SYSCLK / 4 100 = SYSCLK / 6 101 = SYSCLK / 8 110 = SYSCLK / 12 111 = SYSCLK / 16 Enable Class D Speaker Outputs 00 = Off 01 = Left speaker only 10 = Right speaker only 11 = Left and right speakers enabled
R49 (31h) Class D Control (1)
7:6
SPK_OP_EN [1:0]
00
Table 22 Class D Control Registers The class D outputs require a PWM switching clock, which is derived from SYSCLK. This clock should not be altered or disabled while the class D outputs are enabled. See "Clocking and Sample Rates" for more information.
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VOLUME UPDATES
Preliminary Technical Data
Volume settings will not be applied to input or output PGAs until a '1' is written to one of the update bits (IPVU, OUT1VU, SPKVU bits). This is to allow left and right channels to be updated at the same time, as shown in Figure 16.
Figure 16 Simultaneous Left and Right Volume Updates If the volume is adjusted while the signal is a non-zero value, an audible click can occur as shown in Figure 17.
Figure 17 Click Noise During Volume Update In order to prevent this click noise, a zero cross function is provided. When enabled, this will cause the PGA volume to update only when a zero crossing occurs, minimising click noise as shown in Figure 18.
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Preliminary Technical Data
WM8956
Figure 18 Volume Update Using Zero Cross Detection If there is a long period where no zero-crossing occurs, a timeout circuit in the WM8956 will automatically update the volume. The volume updates will occur between one and two timeout periods, depending on when the volume update bit is set as shown in Figure 19. The TOEN register bit must be set to enable this timeout function. The timeout period is set by TOCLKSEL.
Figure 19 Volume Update After Timeout
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HEADPHONE JACK DETECT
Preliminary Technical Data
The GPIO1, LINPUT3/JD2 and RINPUT3/JD3 pins can be selected as headphone jack detect inputs to automatically disable the speaker output and enable the headphone output e.g. when a headphone is plugged into a jack socket. In this mode, enabled by setting HPSWEN, the headphone detect input pin switches between headphone and speaker outputs (e.g. when the pin is connected to a mechanical switch in the headphone socket to detect plug-in). The HPSEL[1:0] bits select the input pin used for this function. The HPSWPOL bit reverses the pin's polarity. Note that the LOUT1, ROUT1, SPKL and SPKR bits in register 26 must also be set for headphone and speaker output (see Table 23 and Table 24). TOEN must also be set to enable the clock which is used for de-bouncing the jack detect input. TOCLKSEL selects a fast or slow de-bounce period. Note that SYSCLK must be enabled to use this function. When using capless mode, the OUT3CAP bit should be enabled so that OUT3 is enabled/disabled at the same time as HP_L and HP_R to prevent pop noise. The debounced headphone detect signal can also be output to the GPIO1 pin (See GPIO section). This function is not available when using GPIO1 as an input. When using the GPIO1 pin as a headphone detect input, the ALRCGPIO register bit needs to be set to 1 (See GPIO section for more information). Note: When LINPUT3 or RINPUT3 is used as the headphone detect input, the thresholds become CMOS levels (0.3 AVDD / 0.7 AVDD). HPSWEN HPSWPOL L/ROUT1 SPKL/R HEADPHONE HEADPHONE ENABLED DETECT PIN (AND OUT3 (REG. 26) (AND OUT3 IN IN (LINPUT3/JD2, CAPLESS RINPUT3/JD3 OR CAPLESS MODE) MODE) GPIO1) (REG. 26) X X X X 0 0 1 1 0 0 1 1 0 0 1 1 X X 0 1 0 1 X X 0 1 0 1 0 1 X X X X 0 1 no no yes yes no no no yes no yes no no SPEAKER ENABLED
0 0 0 0 1 1 1 1 1 1 1 1
X X X X 0 0 0 0 1 1 1 1
no yes no yes no yes no no no no no yes
Table 23 Headphone Jack Detect Operation
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Preliminary Technical Data
WM8956
REGISTER ADDRESS R24 (18h) Additional Control (2) BIT 6 LABEL HPSWEN 0 DEFAULT DESCRIPTION Headphone Switch Enable 0 = Headphone switch disabled 1 = Headphone switch enabled Headphone Switch Polarity 0 = HPDETECT high = headphone 1 = HPDETECT high = speaker Capless Mode Headphone Switch Enable 0 = OUT3 unaffected by jack detect events 1 = OUT3 enabled and disabled together with HP_L and HP_R in response to jack detect events Headphone Switch Input Select 0X = GPIO1 used for jack detect input (Requires pin to be configured as a GPIO using ALRCGPIO) 10 = JD2 used for jack detect input 11 = JD3 used for jack detect input Slow Clock Enable (Must be enabled for jack detect de-bounce) 0 = Slow Clock Disabled 1 = Slow Clock Enabled Slow Clock Selection (Used for volume update timeouts and for jack detect debounce) 0 = SYSCLK / 221 (Slower Response) 1 = SYSCLK / 219 (Faster Response)
5
HPSWPOL
0
R27 (1Bh) Additional Control (3)
3
OUT3CAP
0
R48 (30h) Additional Control (4)
3:2
HPSEL[1:0]
00
R23 (17h) Additional Control (1)
0
TOEN
0
1
TOCLKSEL
0
Table 24 Headphone Jack Detect
Figure 20 Example Headset Detection Circuit Using Normally-Open Switch
Figure 21 Example Headset Detection Circuit Using Normally-Closed Switch
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THERMAL SHUTDOWN
Preliminary Technical Data
The speaker and headphone outputs can drive very large currents. To protect the WM8956 from overheating a thermal shutdown circuit is included and is enabled by default. If the device temperature reaches approximately 1500C and the thermal shutdown circuit is enabled (TSDEN = 1; TSENSEN = 1) the speaker and headphone amplifiers (HP_L, HP_R, SPK_LP, SPK_LN, SPK_RP, SPK_RN and OUT3) will be disabled. This feature can be disabled to save power when the device is in standby mode. TSENSEN must be set to 1 to enable the temperature sensor when using the TSDEN thermal shutdown function. The output of the temperature sensor can also be output to the GPIO1 pin. REGISTER ADDRESS R23 (17h) Additional Control (1) BIT 8 LABEL TSDEN 1 DEFAULT DESCRIPTION Thermal Shutdown Enable 0 = Thermal shutdown disabled 1 = Thermal shutdown enabled (TSENSEN must be enabled for this function to work) Temperature Sensor Enable 0 = Temperature sensor disabled 1 = Temperature sensor enabled
R48 (30h) Additional Control (4)
1
TSENSEN
1
Table 25 Thermal Shutdown
GENERAL PURPOSE INPUT/OUTPUT
The WM8956 has two dual purpose GPIO pins and one dedicated GPIO pin. * * * LINPUT3/JD2: Analogue input or headphone detect input. RINPUT3/JD3: Analogue input or headphone detect input. GPIO1: GPIO pin.
The GPIO1 pin can be configured as a headphone detect input, or one of a number of GPIO output functions as shown in Table 26. The default configuration for the LINPUT3 and RINPUT2 pins is to be analogue inputs. The ALRCGPIO bit must be set to enable GPIO1 pin to operate as a GPIO.
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Preliminary Technical Data
WM8956
REGISTER ADDRESS R9 (09h) Audio Interface (2) R48 (30h) Additional Control (4) BIT 6 LABEL ALRCGPIO DEFAULT 0 DESCRIPTION GPIO1 Pin Function Select 0 = GPIO1 pin disabled 1 = GPIO1 pin configured as GPIO GPIO1 GPIO Function Select: 000 = Jack detect input 001 = Reserved 010 = Temperature ok 011 = Debounced jack detect output 100 = SYSCLK output 101 = PLL lock 110 = Logic 0 111 = Logic 1 GPIO Polarity Invert 0 = Non inverted 1 = Inverted SYSCLK Output to GPIO Clock Division Ratio 000 = SYSCLK 001 = SYSCLK / 2 010 = SYSCLK / 3 011 = SYSCLK / 4 100 = SYSCLK / 5.5 101 = SYSCLK / 6
6:4
GPIOSEL [2:0]
000
7
GPIOPOL
0
R52 (34h) Clocking (2)
8:6
OPCLKDIV [2:0]
000
Table 26 GPIO Control Slow clock must be enabled (TOEN = 1) when using the jack detect function. This slow clock is used to debounce the jack detect input. The debounce period can be selected using TOCLKSEL. The temperature sensor must be enabled for the "Temperature ok" GPIO output to function properly. For further details of the Jack detect operation see the Headphone Switch section.
DIGITAL AUDIO INTERFACE
The digital audio interface is used for inputting DAC data into the WM8956. It uses three pins: DACDAT: DAC data input DACLRC: DAC data alignment clock BCLK: Bit clock, for synchronisation The clock signals BCLK and DACLRC can be outputs when the WM8956 operates as a master, or inputs when it is a slave (see Master and Slave Mode Operation, below). Four different audio data formats are supported: * * * * Left justified Right justified I 2S DSP mode
All four of these modes are MSB first. They are described in Audio Data Formats, below. Refer to the Electrical Characteristic section for timing information.
MASTER AND SLAVE MODE OPERATION
The WM8956 can be configured as either a master or slave mode device. As a master device the WM8956 generates BCLK and DACLRC and thus controls sequencing of the data transfer on DACDAT. In slave mode, the WM8956 responds with data to clocks it receives over the digital audio interface. The mode can be selected by writing to the MS bit. Master and slave modes are illustrated below.
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Preliminary Technical Data
BCLK DACLRC DACDAT DSP ENCODER/ DECODER
BCLK DACLRC DACDAT DSP ENCODER/ DECODER
WM8956 DAC
WM8956 DAC
Figure 22 Master Mode
Figure 23 Slave Mode
BCLK DIVIDE
The BCLK frequency is controlled by BCLKDIV[3:0]. See Clocking and Sample Rates section for more information.
AUDIO DATA FORMATS
In Left Justified mode, the MSB is available on the first rising edge of BCLK following a LRCLK transition. The other bits up to the LSB are then transmitted in order. Depending on word length, BCLK frequency and sample rate, there may be unused BCLK cycles before each LRCLK transition.
Figure 24 Left Justified Audio Interface (assuming n-bit word length) In Right Justified mode, the LSB is available on the last rising edge of BCLK before a LRCLK transition. All other bits are transmitted before (MSB first). Depending on word length, BCLK frequency and sample rate, there may be unused BCLK cycles after each LRCLK transition.
Figure 25 Right Justified Audio Interface (assuming n-bit word length) In I S mode, the MSB is available on the second rising edge of BCLK following a LRCLK transition. The other bits up to the LSB are then transmitted in order. Depending on word length, BCLK frequency and sample rate, there may be unused BCLK cycles between the LSB of one sample and the MSB of the next.
2
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Figure 26 I2S Justified Audio Interface (assuming n-bit word length) In DSP/PCM mode, the left channel MSB is available on either the 1 (mode B) or 2 (mode A) rising edge of BCLK (selectable by LRP) following a rising edge of LRC. Right channel data immediately follows left channel data. Depending on word length, BCLK frequency and sample rate, there may be unused BCLK cycles between the LSB of the right channel data and the next sample. In device master mode, the LRC output will resemble the frame pulse shown in Figure 27 and Figure 28. In device slave mode, Figure 29 and Figure 30, it is possible to use any length of frame pulse less than 1/fs, providing the falling edge of the frame pulse occurs greater than one BCLK period before the rising edge of the next frame pulse.
st nd
Figure 27 DSP/PCM Mode Audio Interface (mode A, LRP=0, Master)
Figure 28 DSP/PCM Mode Audio Interface (mode B, LRP=1, Master)
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Preliminary Technical Data
Figure 29 DSP/PCM Mode Audio Interface (mode A, LRP=0, Slave)
Figure 30 DSP/PCM Mode Audio Interface (mode B, LRP=1, Slave)
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Preliminary Technical Data
WM8956
AUDIO INTERFACE CONTROL
The register bits controlling audio format, word length and master / slave mode are summarised in Table 27. MS selects audio interface operation in master or slave mode. In Master mode BCLK and DACLRC are outputs. The frequency of DACLRC is set by the DACDIV bits and the frequency of BCLK is set by the BCLKDIV bits (See "Clocking and Sample Rates"). In Slave mode BCLK and DACLRC are inputs. REGISTER ADDRESS R7 (07h) Digital Audio Interface Format BIT 7 LABEL BCLKINV DEFAULT 0 DESCRIPTION BCLK invert bit (for master and slave modes) 0 = BCLK not inverted 1 = BCLK inverted Master / Slave Mode Control 0 = Enable slave mode 1 = Enable master mode Left/Right DAC Channel Swap 0 = Output left and right data as normal 1 = Swap left and right DAC data in audio interface Right, left and I S modes - LRCLK polarity 0 = normal LRCLK polarity 1 = invert LRCLK polarity DSP Mode - mode A/B select 0 = MSB is available on 2nd BCLK rising edge after LRC rising edge (mode A) 1 = MSB is available on 1st BCLK rising edge after LRC rising edge (mode B) 3:2 WL[1:0] 10 Audio Data Word Length 00 = 16 bits 01 = 20 bits 10 = 24 bits 11 = 32 bits (see Note) Audio Data Format Select 00 = Right justified 01 = Left justified 10 = I2S Format 11 = DSP Mode
2
6
MS
0
5
DLRSWAP
0
4
LRP
0
1:0
FORMAT[1:0]
10
Table 27 Audio Data Format Control Note: Right Justified mode does not support 32-bit data.
AUDIO INTERFACE OUTPUT TRISTATE
Register bit TRIS, register 24(18h) bit[3] can be used to switch DACLRC and BCLK to inputs. In Slave mode (MS=0) DACLRC and BCLK are by default configured as inputs (see Table 28). REGISTER ADDRESS R24 (18h) Additional Control (2) BIT 3 LABEL TRIS DEFAULT 0 DESCRIPTION Switches DACLRC and BCLK to inputs. 0 = DACLRC and BCLK are inputs (slave mode) or outputs (master mode) 1 = DACLRC and BCLK are inputs
Table 28 Tri-stating the Audio Interface
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MASTER MODE DACLRC ENABLE
Preliminary Technical Data
In master mode, by default DACLRC and BCLK are disabled when the DACs are both disabled.
Figure 31 Master Mode Clock Output Control
COMPANDING
The WM8956 supports A-law and -law companding. Companding can be enabled on the DAC audio interface by writing the appropriate value to the DACCOMP register bit. REGISTER ADDRESS R9 (09h) Audio Interface (2) BIT 4:3 LABEL DACCOMP DEFAULT 00 DESCRIPTION DAC companding 00 = off 01 = reserved 10 = -law 11 = A-law 0 = off 1 = device operates in 8-bit mode.
5
WL8
0
Table 29 Companding Control Companding involves using a piecewise linear approximation of the following equations (as set out by ITU-T G.711 standard) for data compression: -law (where =255 for the U.S. and Japan): F(x) = ln( 1 + |x|) / ln( 1 + ) A-law (where A=87.6 for Europe): F(x) = A|x| / ( 1 + lnA) F(x) = ( 1 + lnA|x|) / (1 + lnA) } for x 1/A } for 1/A x 1 -1 x 1
The companded data is also inverted as recommended by the G.711 standard (all 8 bits are inverted for -law, all even data bits are inverted for A-law). The data will be transmitted as the first 8 MSB's of data. Companding converts 13 bits (-law) or 12 bits (A-law) to 8 bits using non-linear quantization. The input data range is separated into 8 levels, allowing low amplitude signals better precision than that of high amplitude signals. This is to exploit the operation of the human auditory system, where louder sounds do not require as much resolution as quieter sounds. The companded signal is an 8-bit word containing sign (1-bit), exponent (3-bits) and mantissa (4-bits). Setting the WL8 register bit allows the device to operate with 8-bit data. In this mode it is possible to use 8 BCLK cycles per LRC frame. When using DSP mode B, this allows 8-bit data words to be output consecutively every 8 BCLK cycles and can be used with 8-bit data words using the A-law and u-law companding functions.
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Preliminary Technical Data
WM8956
BIT7 SIGN BIT[6:4] EXPONENT BIT[3:0] MANTISSA
Table 30 8-bit Companded Word Composition
u-law Companding
1 120 100 Companded Output 80 60 40 20 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Normalised Input 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Normalised Output
Figure 32 -Law Companding
A-law Companding
1 120 100 Companded Output 80 60 40 20 0 0 0.2 0.4 0.6 0.8 1 Normalised Input 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Normalised Output
Figure 33 A-Law Companding
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CLOCKING AND SAMPLE RATES
Preliminary Technical Data
Figure 34 Clocking Scheme Clocks for the DACs, the DSP core functions, the digital audio interface and the class D outputs are all derived from SYSCLK as show in Figure 34. SYSCLK can either be derived directly from MCLK, or generated from a PLL using MCLK as a reference. The clock source is selected by CLKSEL. Many commonly-used audio sample rates can be derived directly from MCLK, while the PLL provides additional flexibility. The DAC sample rate is selectable, relative to SYSCLK, using DACDIV. In master mode, BCLK is also derived from SYSCLK via a programmable clock divide (BCLKDIV). When the GPIO1 pin is configured as a GPIO, a clock derived from SYSCLK can be output on this pin to provide clocking for other parts of the system. The frequency of this output clock is set by OPCLKDIV. A slow clock derived from SYSCLK is used to de-bounce the headphone detect function, and to set the timeout period for volume updates when zero-cross functions are used. This clock is enabled by TOEN and its frequency is set by TOCLKSEL. The class D outputs require a clock, and this is also derived from SYSCLK via a programmable divider (DCLKDIV) as shown in Figure 34. The class D switching clock should be set between 700kHz and 800kHz.
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WM8956
The class D switching clock should not be disabled when the speaker outputs are active, as this would prevent the speaker outputs from functioning. The class D switching clock frequency should not be altered while the speaker outputs are active as this may generate an audible click. Table 31 shows the clocking and sample rate controls for MCLK input, BCLK output (in master mode), DACs, class D outputs and GPIO clock output. Refer to Table 32 for example clocking configurations. REGISTER ADDRESS R4 (04h) Clocking (1) BIT 5:3 LABEL DACDIV [2:0] DEFAULT 000 DESCRIPTION DAC Sample rate divider (Also determines DACLRC in master mode) 000 = SYSCLK / (1.0 * 256) 001 = SYSCLK / (1.5 * 256) 010 = SYSCLK / (2 * 256) 011 = SYSCLK / (3 * 256) 100 = SYSCLK / (4 * 256) 101 = SYSCLK / (5.5 * 256) 110 = SYSCLK / (6 * 256) 111 = Reserved SYSCLK Pre-divider. Clock source (MCLK or PLL output) will be divided by this value to generate SYSCLK. 00 = Divide SYSCLK by 1 01 = Reserved 10 = Divide SYSCLK by 2 11 = Reserved SYSCLK selection 0 = SYSCLK derived from MCLK 1 = SYSCLK derived from PLL output 111 Class D switching clock divider. 000 = SYSCLK / 1.5 001 = SYSCLK / 2 010 = SYSCLK / 3 011 = SYSCLK / 4 100 = SYSCLK / 6 101 = SYSCLK / 8 110 = SYSCLK / 12 111 = SYSCLK / 16 BCLK Frequency (Master Mode) 0000 = SYSCLK 0001 = SYSCLK / 1.5 0010 = SYSCLK / 2 0011 = SYSCLK / 3 0100 = SYSCLK / 4 0101 = SYSCLK / 5.5 0110 = SYSCLK / 6 0111 = SYSCLK / 8 1000 = SYSCLK / 11 1001 = SYSCLK / 12 1010 = SYSCLK / 16 1011 = SYSCLK / 22 1100 = SYSCLK / 24 1101 to 1111 = SYSCLK / 32
2:1
SYSCLKDIV [1:0]
00
0
CLKSEL
0
R8 (08h) Clocking (2)
8:6
DCLKDIV
3:0
BCLKDIV[3:0]
0000
Table 31 DAC and BCLK Control
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SYSCLK (=MCLK OR PLL OUTPUT) (MHz) DACDIV DAC SAMPLE RATE (kHz) 48 32 24 16 12 (Not used) 8 Reserved 44.1 (Not used) 22.05 (Not used) 11.025 8.018 (Not used) Reserved 8 (Not used) (Not used) (Not used) (Not used) (Not used) (Not used) Reserved
Preliminary Technical Data
000 (=1) 001 (=1.5) 010 (=2) 12.288 011 (=3) 100 (=4) 101 (=5.5) 110 (=6) 111 000 (=1) 001 (=1.5) 010 (=2) 11.2896 011 (=3) 100 (=4) 101 (=5.5) 110 (=6) 111 000 (=1) 001 (=1.5) 010 (=2) 2.048 011 (=3) 100 (=4) 101 (=5.5) 110 (=6) 111 Table 32 DAC Sample Rates
When operating in slave mode, the host device must provide sufficient BCLK cycles to transfer complete data words to the DACs. Table 33 shows the maximum word lengths supported for a given SYSCLK and BCLKDIV, assuming that the DACs are running at maximum rate (i.e. DACDIV[2:0]=000).
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Preliminary Technical Data
WM8956
SYSCLK BCLKDIV[3:0] (=MCLK OR PLL OUTPUT) (MHz) 0000 (=1) 0001 (=1.5) 0010 (=2) 0011 (=3) 0100 (=4) 0101 (=5.5) 0110 (=6) 12.288 0111 (=8) 1000 (=11) 1001 (=12) 1010 (=16) 1011 (=22) 1100 (=24) 1101 (=32) 1110 (=32) 1111 (=32) 0000 (=1) 0001 (=1.5) 0010 (=2) 0011 (=3) 0100 (=4) 0101 (=5.5) 0110 (=6) 11.2896 0111 (=8) 1000 (=11) 1001 (=12) 1010 (=16) 1011 (=22) 1100 (=24) 1101 (=32) 1110 (=32) 1111 (=32) Table 33 BCLK Divider in Master Mode BCLK RATE MAXIMUM WORD LENGTH (MASTER MODE) (AT MAXIMUM DAC SAMPLE RATE) (MHz) 12.288 8.192 6.144 4.096 3.072 2.2341818 2.048 1.536 1.117091 1.024 0.768 0.558545 0.512 0.384 0.384 0.384 11.2896 7.5264 5.6448 3.7632 2.8224 2.052655 1.8816 1.4112 1.026327 0.9408 0.7056 0.513164 0.4704 0.3528 0.3528 0.3528 32 32 32 32 32 20 20 16 8 8 8 N/A N/A N/A N/A N/A 32 32 32 32 32 20 20 16 8 8 8 N/A N/A N/A N/A N/A
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WM8956
OTHER SAMPLE RATE CONTROL BITS
Preliminary Technical Data
The de-emphasis filter and 3D stereo enhance functions all need to be configured for the chosen sample rate when in use, as show in Table 34. DEEMPH, 3DUC and 3DUC should be configured to match the chosen DAC sample rate. REGISTER ADDRESS R5 (05h) DAC Control (1) BIT 2:1 LABEL DEEMPH [1:0] DEFAULT 00 DESCRIPTION De-Emphasis Control 11 = 48kHz sample rate 10 = 44.1kHz sample rate 01 = 32kHz sample rate 00 = No de-emphasis Upper Cut-Off Frequency 0 = High (Recommended for fs>=32kHz) 1 = Low (Recommended for fs<32kHz) Lower Cut-Off Frequency 0 = Low (Recommended for fs>=32kHz) 1 = High (Recommended for fs<32kHz)
R16 (10h) 3D Enhance
6
3DUC
0
5
3DLC
0
Table 34 Additional Sample Rate Controls
PLL
The integrated PLL can be used to generate SYSCLK for the WM8956 or provide clocking for external devices via the GPIO1 pin. The PLL is enabled by the PLLEN register bit. REGISTER ADDRESS R26 (1Ah) Power management (2) R52 (34h) PLL (1) BIT 0 LABEL PLLEN DEFAULT 0 PLL Enable 0 = PLL off 1 = PLL on Enable Integer Mode 0 = Integer mode 1 = Fractional mode DESCRIPTION
5
SDM
0
Table 35 PLLEN Control Bit The PLL frequency ratio R = f2/f1 (See Figure 34) can be set using the register bits PLLK and PLLN: PLLN = int R PLLK = int (224 (R-PLLN)) EXAMPLE: MCLK=12MHz, required clock = 12.288MHz. R should be chosen to ensure 5 < PLLN < 13. There is a fixed divide by 4 in the PLL and a selectable divide by N after the PLL which should be set to divide by 2 to meet this requirement. Enabling the divide by 2 sets the required f2 = 4 x 2 x 12.288MHz = 98.304MHz. R = 98.304 / 12 = 8.192 PLLN = int R = 8 k = int ( 224 x (8.192 - 8)) = 3221225 = 3126E9h
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Preliminary Technical Data REGISTER ADDRESS R52 (34h) PLL N value BIT 4 LABEL PLLPRESCALE DEFAULT 0
WM8956
DESCRIPTION Divide MCLK by 2 before input to PLL 0 = Divide by 1 1 = Divide by 2 Integer (N) part of PLL input/output frequency ratio. Use values greater than 5 and less than 13. Fractional (K) part of PLL1 input/output frequency ratio (treat as one 24-digit binary number).
3:0
PLLN
8h
R53 (35h) PLL K value (1) R54 (36h) PLL K Value (2) R55 (37h) PLL K Value (3)
5:0
PLLK [23:16]
31h
8:0
PLLK [15:8]
26h
8:0
PLLK [7:0]
E9h
Table 36 PLL Frequency Ratio Control The PLL performs best when f2 is between 90MHz and 100MHz. Its stability peaks at N=8. Some example settings are shown in Table 37. POSTSCALE DIVIDE (SYSCLKDIV[1:0]) FIXED POST-DIVIDE PRESCALE DIVIDE (PLLPRESCALE) MCLK (MHz) (f1) DESIRED OUTPUT (SYSCLK) (MHz) f2 (MHz) R N K
12 12 13 13 14.4 14.4 19.2 19.2 19.68 19.68 19.8 19.8 24 24 26 26 27 27
11.2896 12.288 11.2896 12.288 11.2896 12.288 11.2896 12.288 11.2896 12.288 11.2896 12.288 11.2896 12.288 11.2896 12.288 11.2896 12.288
90.3168 98.304 90.3168 98.304 90.3168 98.304 90.3168 98.304 90.3168 98.304 90.3168 98.304 90.3168 98.304 90.3168 98.304 90.3168 98.304
1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
7.5264 8.192 6.947446 7.561846 6.272 6.826667 9.408 10.24 9.178537 9.990243 9.122909 9.929697 7.5264 8.192 6.947446 7.561846 6.690133 7.281778
7h 8h 6h 7h 6h 6h 9h Ah 9h 9h 9h 9h 7h 8h 6h 7h 6h 7h
86C226h 3126E8h F28BD4h 8FD525h 45A1CAh D3A06Eh 6872AFh 3D70A3h 2DB492h FD809Fh 1F76F7h EE009Eh 86C226h 3126E8h F28BD4h 8FD525h B0AC93h 482296h
Table 37 PLL Frequency Examples
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WM8956
Preliminary Technical Data
Device running in master mode with 24-bit data MCLK input at 12.288MHz DAC running at fs=48kHz BCLK running at 64fs
Device running in slave mode with 24-bit data MCLK input at 12.288MHz DAC running at fs=48kHz BCLK supplied from host at 64fs in this example
Device running in master mode with 24-bit data MCLK input at 11.2896MHz DAC running at fs=44.1kHz BCLK running at 64fs in this example
Device running in slave mode with 24-bit data MCLK input at 11.2896MHz DAC running at fs=44.1kHz BCLK supplied from host at 64fs in this example.
Device running in master mode with 24-bit data MCLK input at 12MHz PLL Enabled and configured for SYSCLK=11.2896MHz DAC running at fs=44.1kHz BCLK running at 64fs in this example Class D clocks running at 705.6kHz
Table 38 Example Clocking Schemes
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Preliminary Technical Data
WM8956
CONTROL INTERFACE
2-WIRE SERIAL CONTROL INTERFACE
The WM8956 is controlled by writing to registers through a 2-wire serial control interface. A control word consists of 16 bits. The first 7 bits (B15 to B9) are address bits that select which control register is accessed. The remaining 9 bits (B8 to B0) are data bits, corresponding to the 9 bits in each control register. Many devices can be controlled by the same bus, and each device has a unique 7-bit address (this is not the same as the 7-bit address of each register in the WM8956). The device address is 0011010 (0x34h). The WM8956 operates as a slave device only. The controller indicates the start of data transfer with a high to low transition on SDIN while SCLK remains high. This indicates that a device address and data will follow. All devices on the 2-wire bus respond to the start condition and shift in the next eight bits on SDIN (7-bit address + Read/Write bit, MSB first). If the device address received matches the address of the WM8956 and the R/W bit is `0', indicating a write, then the WM8956 responds by pulling SDIN low on the next clock pulse (ACK). If the address is not recognised or the R/W bit is `1', the WM8956 returns to the idle condition and wait for a new start condition and valid address. Once the WM8956 has acknowledged a correct address, the controller sends the first byte of control data (B15 to B8, i.e. the WM8956 register address plus the first bit of register data). The WM8956 then acknowledges the first data byte by pulling SDIN low for one clock pulse. The controller then sends the second byte of control data (B7 to B0, i.e. the remaining 8 bits of register data), and the WM8956 acknowledges again by pulling SDIN low. The transfer of data is complete when there is a low to high transition on SDIN while SCLK is high. After receiving a complete address and data sequence the WM8956 returns to the idle state and waits for another start condition. If a start or stop condition is detected out of sequence at any point during data transfer (i.e. SDIN changes while SCLK is high), the device jumps to the idle condition.
SDIN
DEVICE ADDRESS (7 BITS)
RD / WR BIT
ACK (LOW)
CONTROL BYTE 1 (BITS 15 TO 8)
ACK (LOW)
CONTROL BYTE 2 (BITS 7 TO 0)
ACK (LOW)
SCLK START STOP
register address and 1st register data bit
remaining 8 bits of register data
Figure 35 2-Wire Serial Control Interface
POWER MANAGEMENT
The WM8956 has three control registers that allow users to select which functions are active. For minimum power consumption, unused functions should be disabled. To avoid any pop or click noise, it is important to enable or disable functions in the correct order (see Applications Information). VMIDSEL is the enable for the Vmid reference, which defaults to disabled and can be enabled as a 2x50k potential divider or, for low power maintenance of Vref when all other blocks are disabled, as a 2x250k potential divider.
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WM8956
REGISTER ADDRESS R25 (19h) Power Management (1) BIT 8:7 LABEL VMIDSEL DEFAULT 00
Preliminary Technical Data
DESCRIPTION Vmid Divider Enable and Select 00 = Vmid disabled (for OFF mode) 01 = 2 x 50k divider enabled (for playback / record) 10 = 2 x 250k divider enabled (for lowpower standby) 11 = 2 x 5k divider enabled (for fast startup) VREF (necessary for all other functions) 0 = Power down 1 = Power up Analogue Input PGA and Boost Left 0 = Power down 1 = Power up (Note: LMIC must also be set to enable the PGA) Analogue Input PGA and Boost Right 0 = Power down 1 = Power up (Note: RMIC must also be set to enable the PGA) MICBIAS 0 = Power down 1 = Power up Master Clock Disable 0 = Master clock enabled 1 = Master clock disabled DAC Left 0 = Power down 1 = Power up DAC Right 0 = Power down 1 = Power up LOUT1 Output Buffer 0 = Power down 1 = Power up ROUT1 Output Buffer 0 = Power down 1 = Power up SPK_LP/SPK_LN Output PGA. 0 = Power down 1 = Power up (Note: Speaker output also requires SPK_OP_EN[0] to be set) SPK_RP/SPK_RN Output PGA 0 = Power down 1 = Power up (Note: Speaker output also requires SPK_OP_EN[1] to be set) OUT3 Output Buffer 0 = Power down 1 = Power up
6
VREF
0
5
AINL
0
4
AINR
0
1
MICB
0
0
DIGENB
0
R26 (1Ah) Power Management (2)
8
DACL
0
7
DACR
0
6
LOUT1
0
5
ROUT1
0
4
SPKL
0
3
SPKR
0
1
OUT3
0
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Preliminary Technical Data REGISTER ADDRESS BIT 0 LABEL PLL_EN DEFAULT 0 DESCRIPTION PLL Enable 0 = Power down 1 = Power up
WM8956
R47 (2Fh) Power Management (3)
5
LMIC
Left Input PGA Enable 0 = Power down 1 = Power up (Note: PGA also requires AINL to be set) RIght Input PGA Enable 0 = Power down 1 = Power up (Note: PGA also requires AINR to be set) Left Output Mixer Enable 0 = Power down 1 = Power up Right Output Mixer Enable 0 = Power down 1 = Power up
4
RMIC
3
LOMIX
2
ROMIX
Table 39 Power Management
STOPPING THE MASTER CLOCK
In order to minimise power consumed in the digital core of the WM8956, the master clock may be stopped in Standby and OFF modes. If this cannot be done externally at the clock source, the DIGENB bit (R25, bit 0) can be set to stop the MCLK signal from propagating into the device core. In Standby mode, setting DIGENB will typically provide an additional power saving on DCVDD of 20uA. However, since setting DIGENB has no effect on the power consumption of other system components external to the WM8956, it is preferable to disable the master clock at its source wherever possible. MCLK should not be stopped while the class D outputs are enabled, as this would prevent the outputs from functioning. REGISTER ADDRESS R25 (19h) Additional Control (1) 0 BIT LABEL DIGENB 0 DEFAULT DESCRIPTION Master clock disable 0 = Master clock enabled 1 = Master clock disabled
Table 40 Enabling the Master Clock NOTE: Before DIGENB can be set, the control bits DACL and DACR must be set to zero and a waiting time of 1ms must be observed. Any failure to follow this procedure may prevent DACs from re-starting correctly.
SAVING POWER AT HIGHER SUPPLY VOLTAGE
The AVDD supply of the WM8956 can operate beteen 2.7V and 3.6V. By default, all analogue circuitry on the device is optimized to run at 3.3V. This set-up is also good for all other supply voltages down to 2.7V. At lower voltages, performance can be improved by increasing the bias current by setting VSEL[1:0] = 01. If low power operation is preferred the bias current can be left at the default setting. This is controlled as shown below. REGISTER ADDRESS R23 (17h) Additional Control (1) BIT 7:6 LABEL VSEL [1:0] DEFAULT 11 DESCRIPTION Analogue Bias Optimisation 00 = Reserved 01 = Increased bias current, optimized for AVDD=2.7V 1X = Lowest bias current, optimized for AVDD=3.3V
Table 41 Bias Optimisation
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WM8956 REGISTER MAP
REGISTER R0 (00h) R1 (01h) R2 (02h) R3 (03h) R4 (04h) R5 (05h) R6 (06h) R7 (07h) R8 (08h) R9 (09h) R10 (0Ah) R11 (0Bh) R12 (0Ch) R13 (0Dh) R14 (0Eh) R15 (0Fh) R16 (10h) R17 (11h) R18 (12h) R19 (13h) R20 (14h) R21 (15h) R22 (16h) R23 (17h) R24 (18h) R25 (19h) R26 (1Ah) R27 (1Bh) R28 (1Ch) R29 (1Dh) R30 (1Eh) R31 (1Fh) R32 (20h) R33 (21h) R34 (22h) R35 (23h) R36 (24h) R37 (25h) R38 (26h) R39 (27h) R40 (28h) R41 (29h) R42 (2Ah) R43 (2Bh) R44 (2Ch) R45 (2Dh) R46 (2Eh) R47 (2Fh) R48 (30h) R49 (31h) R50 (32h) R51 (33h) R52 (34h) R53 (35h) R54 (36h) R55 (37h) remarks Left Input volume Right Input volume LOUT1 volume ROUT1 volume Clocking (1) DAC Control (CTR1) DAC Control (CTR2) Audio Interface Clocking (2) Audio Interface Left DAC volume Right DAC volume Reserved Reserved Reserved Reset 3D control Reserved Reserved Reserved Reserved Reserved Reserved Additional control(1) Additional control(2) Pwr Mgmt (1) Pwr Mgmt (2) Additional Control (3) Anti-pop 1 Anti-pop 2 Reserved Reserved L input signal path R input signal path Left out Mix (1) Reserved Reserved Right out Mix (2) Mono out Mix (1) Mono out Mix (2) LOUT2 volume ROUT2 volume MONOOUT volume Input boost mixer (1) Input boost mixer (2) Bypass (1) Bypass (2) Pwr Mgmt (3) Additional Control (4) Class D Control (1) Reserved Class D Control (3) PLL N PLL K 1 PLL K 2 PLL K 3 0 0 0 0 0 1 0 0 0 0 TSDEN 0 VMIDSEL[1:0] DACL 0 0 0 0 0 LMN1 RMN1 LD2LO 0 0 RD2RO 0 0 SPKVU SPKVU 0 0 0 0 0 0 0 0 0 0 DACR 0 POBCTRL 0 0 0 LMP3 RMP3 LI2LO 0 0 RI2RO L2MO R2MO SPKLZC SPKRZC 0 0 0 LB2LO RB2RO 0 GPIOPOL SPK_OP_EN[1:0] 0 1 OPCLKDIV[2:0] 1 0 SDM 0 MOUTVOL 0 LIN3BOOST[2:0] RIN3BOOST[2:0] LB2LOVOL[2:0] RB2ROVOL[2:0] LMIC GPIOSEL[2:0] 1 0 1 0 DCGAIN[2:0] PLLRESCALE PLLK[23:16] PLLK[15:8] PLLK[7:0] 0 1 RMIC 0 0 LOMIX 0 0 0 1 1 0 0 0 0 0 0 1 1 VSEL[1:0] HPSWEN VREF LOUT1 VROI 0 DISOP 0 0 LMP2 RMP2 0 0 0 DACVU DACVU 0 0 0 0 0 0 0 0 0 0 0 0 Bit[8] IPVU IPVU OUT1VU OUT1VU 0 0 0 0 Bit[7] LINMUTE RINMUTE LO1ZC RO1ZC 0 DACDIV2 0 BCLKINV DCLKDIV[2:0] 0 ALRCGPIO 0 0 DACPOL[1:0] MS DLRSWAP 0 WL8 0 DACDIV[2:0] 0 0 LRP 0 DACCOMP[1:0] LDACVOL[7:0] RDACVOL[7:0] 0 0 0 0 0 0 0 0 0 0 DACMU DACSMM Bit[6] LIZC RIZC Bit[5] Bit[4] Bit[3] Bit[2]
Preliminary Technical Data
Bit[1]
Bit[0]
default 0_1001_0111 0_1001_0111 0_0000_0000 0_0000_0000
LINVOL[5:0] RINVOL[5:0] LOUT1VOL[6:0] ROUT1VOL[6:0] SYSCLKDIV[1:0] DEEMPH[1:0] DACMR DACSLOPE FORMAT[1:0] BCLKDIV[3:0] 0 0 CLKSEL 0 0
0_0000_0000 0_0000_1000 0_0000_0000 0_0000_1010 1_1100_0000 0_0000_0000 0_1111_1111 0_1111_1111
WL[1:0]
0 0 0
0 0 0
0_0000_0000 0_0000_0000 0_0000_0000 not reset
writing to this register resets all registers to their default state 3DUC 1 0 0 0 1 1 3DLC 1 0 1 0 0 0 0 HPSWPOL AINL ROUT1 0 0 1 0 1 0 0 0 DMONOMIX 0 AINR SPKL 0 BUFDCOPEN DRES[1:0] 0 0 3DDEPTH[3:0] 1 0 0 0 0 0 0 TRIS 0 SPKR OUT3CAP BUFIOEN 0 0 0 LMIC2B RMIC2B 0 1 1 0 0 0 0 0 0 0 SPKLVOL[6:0] SPKRVOL[6:0] 0 0 LIN2BOOST[2:0] RIN2BOOST[2:0] 0 0 ROMIX 0 0 0 TSENSEN 1 1 1 0 ACGAIN[2:0] PLLN[3:0] 0 0 0 0 0 0 0 MBSEL 1 1 0 0 0 0 0 0 0 0 0 0 0 SOFT_ST 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 1 TOCLKSEL 0 MICB OUT3 0 0 0 0 0 0 0 0 0 0 0 0 0 3DEN 1 0 0 0 1 1 TOEN 0 DIGENB PLL_EN 0 HPSTBY 0 0 0 0 0 0 0 0 0 0 0
0_0000_0000 0_0111_1011 1_0000_0000 0_0011_0010 0_0000_0000 0_1100_0011 0_1100_0011 1_1100_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0000_0000 1_0000_0000 1_0000_0000 0_0101_0000 0_0101_0000 0_0101_0000 0_0101_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0000_0000 0_0100_0000 0_0000_0000 0_0000_0000 0_0101_0000 0_0101_0000 0_0000_0000 0_0000_0010 0_0011_0111 0_0100_1101 0_1000_0000 0_0000_1000 0_0011_0001 0_0010_0110 0_1110_1001
LMICBOOST[1:0] RMICBOOST[1:0] LI2LOVOL[2:0] 0 0 RI2ROVOL[2:0] 0 0
HPSEL[1:0]
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Preliminary Technical Data
WM8956
REGISTER BITS BY ADDRESS
REGISTER ADDRESS R0 (00h) Left Input Volume BIT 8 IPVU LABEL DEFAULT N/A DESCRIPTION Input PGA Volume Update Writing a 1 to this bit will cause left and right input PGA volumes to be updated (LINVOL and RINVOL) Left Input PGA Analogue Mute 1 = Enable Mute 0 = Disable Mute Note: IPVU must be set to un-mute. Left Input PGA Zero Cross Detector 1 = Change gain on zero cross only 0 = Change gain immediately Left Input PGA Volume Control 111111 = +30dB 111110 = +29.25dB . . 0.75dB steps down to 000000 = -17.25dB Input PGA Volume Update Writing a 1 to this bit will cause left and right input PGA volumes to be updated (LINVOL and RINVOL) Right Input PGA Analogue Mute 1 = Enable Mute 0 = Disable Mute Note: IPVU must be set to un-mute. Right Input PGA Zero Cross Detector 1 = Change gain on zero cross only 0 = Change gain immediately Right Input PGA Volume Control 111111 = +30dB 111110 = +29.25dB . . 0.75dB steps down to 000000 = -17.25dB Headphone Output PGA Volume Update Writing a 1 to this bit will cause left and right headphone output volumes to be updated (LOUT1VOL and ROUT1VOL) Left Headphone Output Zero Cross Enable 0 = Change gain immediately 1 = Change gain on zero cross only LOUT1 Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Headphone Output PGA Volume Update Writing a 1 to this bit will cause left and right headphone output volumes to be updated (LOUT1VOL and ROUT1VOL) Right Headphone Output Zero Cross Enable 0 = Change gain immediately 1 = Change gain on zero cross only REFER TO Input Signal Path
7
LINMUTE
1
Input Signal Path
6
LIZC
0
Input Signal Path Input Signal Path
5:0
LINVOL[5:0]
010111
R1 (01h) Right Input Volume
8
IPVU
N/A
Input Signal Path
7
RINMUTE
1
Input Signal Path
6
RIZC
0
Input Signal Path Input Signal Path
5:0
RINVOL[5:0]
010111
R2 (02h) LOUT1 Volume
8
OUT1VU
N/A
Analogue Outputs
7
LO1ZC
0
Analogue Outputs Analogue Outputs
6:0
LOUT1VOL[6:0]
0000000
R3 (03h) ROUT1 Volume
8
OUT1VU
N/A
Analogue Outputs
7
RO1ZC
0
Analogue Outputs
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WM8956
REGISTER ADDRESS BIT 6:0 LABEL ROUT1VOL[6:0] DEFAULT 0000000 DESCRIPTION ROUT1 Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Reserved DAC Sample rate divider (Also determines DACLRC in master mode) 000 = SYSCLK / (1.0 * 256) 001 = SYSCLK / (1.5 * 256) 010 = SYSCLK / (2 * 256) 011 = SYSCLK / (3 * 256) 100 = SYSCLK / (4 * 256) 101 = SYSCLK / (5.5 * 256) 110 = SYSCLK / (6 * 256) 111 = Reserved
Preliminary Technical Data REFER TO Analogue Outputs
R4 (04h) Clocking (1)
8:6 5:3 DACDIV[2:0]
000 000
Clocking and Sample Rates
2:1
SYSCLKDIV[1:0]
00
SYSCLK Pre-divider. Clock source (MCLK or PLL output) will be divided by this value to generate SYSCLK. 00 = Divide SYSCLK by 1 01 = Reserved 10 = Divide SYSCLK by 2 11 = Reserved SYSCLK Selection 0 = SYSCLK derived from MCLK 1 = SYSCLK derived from PLL output Reserved DAC 6dB Attenuate Enable 0 = Disabled (0dB) 1 = -6dB Enabled Reserved DAC Digital Soft Mute 1 = Mute 0 = No mute (signal active) De-emphasis Control 11 = 48kHz sample rate 10 = 44.1kHz sample rate 01 = 32kHz sample rate 00 = No de-emphasis Reserved Reserved DAC polarity control: 00 = Polarity not inverted 01 = DAC L inverted 10 = DAC R inverted 11 = DAC L and R inverted Reserved DAC Soft Mute Mode 0 = Disabling soft-mute (DACMU=0) will cause the volume to change immediately to the LDACVOL / RDACVOL settings 1 = Disabling soft-mute (DACMU=0) will cause the volume to ramp up gradually to the LDACVOL / RDACVOL settings
Clocking and Sample Rates
0
CLKSEL
0
Clocking and Sample Rates
R5 (05h) DAC Control (1)
8 7 DACDIV2
0 0
Output Signal Path
6:4 3 DACMU
000 1
Output Signal Path Output Signal Path
2:1
DEEMPH[1:0]
00
0 R6 (06h) DAC Control (2) 8:7 6:5 DACPOL[1:0]
0 00 00
Output Signal Path
4 3 DACSMM
0 0
Output Signal Path
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Preliminary Technical Data REGISTER ADDRESS BIT 2 LABEL DACMR 0 DEFAULT DESCRIPTION DAC Soft Mute Ramp Rate 0 = Fast ramp (fs/2, providing maximum delay of 10.7ms at fs=48k) 1 = Slow ramp (fs/32, providing maximum delay of 171ms at fs=48k) Selects DAC filter characteristics 0 = Normal mode 1 = Sloping stopband Reserved Reserved BCLK invert bit (for master and slave modes) 0 = BCLK not inverted 1 = BCLK inverted Master / Slave Mode Control 0 = Enable slave mode 1 = Enable master mode Left/Right DAC Channel Swap 0 = Output left and right data as normal 1 = Swap left and right DAC data in audio interface Right, left and I2S modes - LRCLK polarity 0 = normal LRCLK polarity 1 = invert LRCLK polarity DSP Mode - mode A/B select 0 = MSB is available on 2nd BCLK rising edge after LRC rising edge (mode A) 1 = MSB is available on 1st BCLK rising edge after LRC rising edge (mode B) 3:2 WL[1:0] 10 Audio Data Word Length 00 = 16 bits 01 = 20 bits 10 = 24 bits 11 = 32 bits (see Note) 00 = Right justified 01 = Left justified 10 = I2S Format 11 = DSP Mode Class D switching clock divider. 000 = SYSCLK / 1.5 (Not recommended) 001 = SYSCLK / 2 010 = SYSCLK / 3 011 = SYSCLK / 4 100 = SYSCLK / 6 101 = SYSCLK / 8 110 = SYSCLK / 12 111 = SYSCLK / 16 Reserved
WM8956
REFER TO Output Signal Path
1
DACSLOPE
0
Output Signal Path
0 R7 (07h) Audio Interface 8 7 BCLKINV
0 0 0
Audio Interface Control Audio Interface Control Audio Interface Control
6
MS
0
5
DLRSWAP
0
4
LRP
0
Audio Interface Control
Audio Interface Control
1:0
FORMAT[1:0]
10
Audio Interface Control
R8 (08h) Clocking (2)
8:6
DCLKDIV[2:0]
111
Class D Speaker Outputs; Clocking and Sample Rates
5:4
00
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WM8956
REGISTER ADDRESS BIT 3:0 LABEL BCLKDIV[3:0] DEFAULT 0000 DESCRIPTION BCLK Frequency (Master Mode) 0000 = SYSCLK 0001 = SYSCLK / 1.5 0010 = SYSCLK / 2 0011 = SYSCLK / 3 0100 = SYSCLK / 4 0101 = SYSCLK / 5.5 0110 = SYSCLK / 6 0111 = SYSCLK / 8 1000 = SYSCLK / 11 1001 = SYSCLK / 12 1010 = SYSCLK / 16 1011 = SYSCLK / 22 1100 = SYSCLK / 24 1101 to 1111 = SYSCLK / 32 Reserved GPIO1 Pin Function Select 0 = GPIO pin function disabled 1 = GPIO pin function enabled
Preliminary Technical Data REFER TO Clocking and Sample Rates
R9 (09h) Audio Interface
8:7 6 ALRCGPIO
00 0
General Purpose Input / Output; Digital Audio Interface Audio Interface Control
5
WL8
0
8-Bit Word Length Select (Used with companding) 0 = Off 1 = Device operates in 8-bit mode. DAC companding 00 = off 01 = reserved 10 = -law 11 = A-law Reserved DAC Volume Update Writing a 1 to this bit will cause left and right DAC volumes to be updated (LDACVOL and RDACVOL) Left DAC Digital Volume Control 0000 0000 = Digital Mute 0000 0001 = -127dB 0000 0010 = -126.5dB ... 0.5dB steps up to 1111 1111 = 0dB DAC Volume Update Writing a 1 to this bit will cause left and right DAC volumes to be updated (LDACVOL and RDACVOL) Right DAC Digital Volume Control 0000 0000 = Digital Mute 0000 0001 = -127dB 0000 0010 = -126.5dB ... 0.5dB steps up to 1111 1111 = 0dB Reserved Reserved Reserved
4:3
DACCOMP[1:0]
00
Audio Interface Control
2:0 R10 (0Ah) Left DAC Volume 8 DACVU
000 N/A
Output Signal Path
7:0
LDACVOL[7:0]
11111111
Output Signal Path
R11 (0Bh) Right DAC Volume
8
DACVU
N/A
Output Signal Path
7:0
RDACVOL[7:0]
11111111
Output Signal Path
R12 (0Ch) R13 (0Dh) R14 (0Eh)
8:0 8:0 8:0
000000000 000000000 000000000
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PTD, July 2007, Rev 2.1 64
Preliminary Technical Data REGISTER ADDRESS R15 (0Fh) Reset R16 {10h) 3D Control BIT 8:0 8 7 6 3DUC Reset LABEL DEFAULT N/A 0 0 0 DESCRIPTION Writing to this register resets all registers to their default state. Reserved Reserved 3D Enhance Filter Upper Cut-Off Frequency 0 = High (Recommended for fs>=32kHz) 1 = Low (Recommended for fs<32kHz) 3D Enhance Filter Lower Cut-Off Frequency 0 = Low (Recommended for fs>=32kHz) 1 = High (Recommended for fs<32kHz) 3D Stereo Depth 0000 = 0% (minimum 3D effect) 0001 = 6.67% .... 1110 = 93.3% 1111 = 100% (maximum 3D effect) 3D Stereo Enhancement Enable 0 = Disabled 1 = Enabled Reserved
WM8956
REFER TO
Output Signal Path Output Signal Path Output Signal Path
5
3DLC
0
4:1
3DDEPTH[3:0]
0000
0
3DEN
0
Output Signal Path
R17 (11h)
8:0
0000001011
R18 (12h) R19 (13h) R20 (14h) R21 (15h) R22 (16h) R23 (17h) Additional Control (1)
8:0 8:0 8:0 8:0 8:0 8 TSDEN
100000000 000110010 000000000 011000011 011000011 1
Reserved Reserved Reserved Reserved Reserved Thermal Shutdown Enable 0 = Thermal shutdown disabled 1 = Thermal shutdown enabled (TSENSEN must be enabled for this function to work) Analogue Bias Optimisation 00 = Reserved 01 = Bias current optimized for AVDD=2.7V 1X = Lowest bias current, optimized for AVDD=3.3V Reserved DAC Mono Mix 0 = Stereo 1 = Mono (Mono MIX output on enabled DACs) Reserved Slow Clock Select (Used for volume update timeouts and for jack detect debounce) 21 0 = SYSCLK / 2 (Slower Response) 1 = SYSCLK / 219 (Faster Response) Enables Slow Clock for Volume Update Timeout and Jack Detect Debounce 0 = Slow clock disabled 1 = Slow clock enabled Reserved Headphone Switch Enable 0 = Headphone switch disabled 1 = Headphone switch enabled Headphone Jack Detect Volume Updates; Headphone Jack Detect Volume Updates; Headphone Jack Detect Output Signal Path Thermal Shutdown
7:6
VSEL[1:0]
11
Power Management
5 4 DMONOMIX
0 0
3:2 1 TOCLKSEL
00 0
0
TOEN
0
R24 (18h) Additional Control (2)
8:7 6 HPSWEN
00 0
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WM8956
REGISTER ADDRESS BIT 5 LABEL HPSWPOL 0 DEFAULT DESCRIPTION Headphone Switch Polarity 0 = HPDETECT high = headphone 1 = HPDETECT high = speaker Reserved TRIS 0
Preliminary Technical Data REFER TO Headphone Jack Detect
4 3
Switches DACLRC and BCLK to inputs. 0 = DACLRC and BCLK are inputs (slave mode) or outputs (master mode) 1 = DACLRC and BCLK are inputs Reserved Vmid Divider Enable and Select 00 = Vmid disabled (for OFF mode) 01 = 2 x 50k divider enabled (for playback / record) 10 = 2 x 250k divider enabled (for low-power standby) 11 = 2 x 5k divider enabled (for fast start-up) VREF (necessary for all other functions) 0 = Power down 1 = Power up Analogue in PGA Left 0 = Power down 1 = Power up Analogue in PGA Right 0 = Power down 1 = Power up Reserved MICBIAS 0 = Power down 1 = Power up Master Clock Disable 0 = Master clock enabled 1 = Master clock disabled DAC Left 0 = Power down 1 = Power up DAC Right 0 = Power down 1 = Power up LOUT1 Output Buffer 0 = Power down 1 = Power up ROUT1 Output Buffer 0 = Power down 1 = Power up SPK_LP/SPK_LN Output Buffers 0 = Power down 1 = Power up SPK_RP/SPK_RN Output Buffers 0 = Power down 1 = Power up Reserved OUT3 Output Buffer 0 = Power down 1 = Power up
Audio Interface Control
2:0 R25 (19h) Power Mgmt (1) 8:7 VMIDSEL[1:0]
000 00
Power Management
6
VREF
0
Power Management Power Management Power Management
5
AINL
0
4
AINR
0
3:2 1 MICB
00 0
Power Management Power Management Power Management Power Management Power Management Power Management Power Management Power Management
0
DIGENB
0
R26 (1Ah) Power Mgmt (2)
8
DACL
0
7
DACR
0
6
LOUT1
0
5
ROUT1
0
4
SPKL
0
3
SPKR
0
2 1 OUT3
0 0
Power Management
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Preliminary Technical Data REGISTER ADDRESS BIT 0 LABEL PLL_EN 0 DEFAULT PLL Enable 0 = Power down 1 = Power up Reserved VREF to Analogue Output Resistance (Disabled Outputs) 0 = 500 VMID to output 1 = 20k VMID to output Reserved Reserved Capless Mode Headphone Switch Enable 0 = OUT3 unaffected by jack detect events 1 = OUT3 enabled and disabled together with HP_L and HP_R in response to jack detect events Reserved Reserved Selects the bias current source for output amplifiers and VMID buffer 0 = VMID / R bias 1 = VGS / R bias Reserved Enables the VGS / R current generator 0 = Disabled 1 = Enabled Enables the VGS / R current generator and the analogue input and output bias 0 = Disabled 1 = Enabled Enables VMID soft start 0 = Disabled 1 = Enabled Reserved Headphone Amplifier Standby 0 = Standby mode disabled (Normal operation) 1 = Standby mode enabled Reserved Discharges the DC-blocking headphone capacitors on HP_L and HP_R 0 = Enabled 1 = Disabled DRES determines the value of the resistors used to discharge the DC-blocking headphone capacitors when DISOP=1 D600 0 0 1 1 3:0 R30 (1Eh) R31 (1Fh) 8:0 8:0 0000 000000000 000000000 Reserved Reserved Reserved D200 0 1 0 1 Resistance 400 200 600 150 DESCRIPTION
WM8956
REFER TO Power Management
R27 (1Bh) Additional Control (3)
8:7 6 VROI
00 0
Enabling the Outputs
5 4 3 OUT3CAP
0 0 0
Headphone Jack Detect
2:0 R28 (1Ch) Anti-Pop 8 7 POBCTRL
000 0 0
6:5 4 BUFDCOPEN
00 0
3
BUFIOEN
0
2
SOFT_ST
0
1 0 HPSTBY
0 0
R29 (1Dh)
8:7 6 DISOP
00 0
5:4
DRES[1:0]
00
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WM8956
REGISTER ADDRESS R32 (20h) Left Input Signal Path BIT 8 LMN1 LABEL 1 DEFAULT DESCRIPTION
Preliminary Technical Data REFER TO Input Signal Path
Connect LINPUT1 to inverting input of Left Input PGA 0 = LINPUT1 not connected to PGA 1 = LINPUT1 connected to PGA Connect LINPUT3 to non-inverting input of Left Input PGA 0 = LINPUT3 not connected to PGA 1 = LINPUT3 connected to PGA (Constant input impedance) Connect LINPUT2 to non-inverting input of Left Input PGA 0 = LINPUT2 not connected to PGA 1 = LINPUT2 connected to PGA (Constant input impedance) Left Channel Input PGA Boost Gain 00 = +0dB 01 = +13dB 10 = +20dB 11 = +29dB Connect Left Input PGA to Left Input Boost Mixer 0 = Not connected 1 = Connected Reserved Connect RINPUT1 to inverting input of Right Input PGA 0 = RINPUT1 not connected to PGA 1 = RINPUT1 connected to PGA Connect RINPUT3 to non-inverting input of Right Input PGA 0 = RINPUT3 not connected to PGA 1 = RINPUT3 connected to PGA (Constant input impedance) Connect RINPUT2 to non-inverting input of Right Input PGA 0 = RINPUT2 not connected to PGA 1 = RINPUT2 connected to PGA (Constant input impedance) Right Channel Input PGA Boost Gain 00 = +0dB 01 = +13dB 10 = +20dB 11 = +29dB Connect Right Input PGA to Right Input Boost Mixer 0 = Not connected 1 = Connected Reserved Left DAC to Left Output Mixer 0 = Disable (Mute) 1 = Enable Path LINPUT3 to Left Output Mixer 0 = Disable (Mute) 1 = Enable Path
7
LMP3
0
Input Signal Path
6
LMP2
0
Input Signal Path
5:4
LMICBOOST[1:0]
00
Input Signal Path
3
LMIC2B
0
Input Signal Path
2:0 R33 (21h) Right Input Signal Path 8 RMN1
000 1
Input Signal Path
7
RMP3
0
Input Signal Path
6
RMP2
0
Input Signal Path
5:4
RMICBOOST[1:0]
00
Input Signal Path
3
RMIC2B
0
Input Signal Path
2:0 R34 (22h) Left Out Mix 8 LD2LO
000 0
Output Signal Path Output Signal Path
7
LI2LO
0
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Preliminary Technical Data REGISTER ADDRESS BIT 6:4 LABEL LI2LOVOL[2:0] DEFAULT 101 DESCRIPTION LINPUT3 to Left Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Reserved Reserved Reserved Right DAC to Right Output Mixer 0 = Disable (Mute) 1 = Enable Path RINPUT3 to Right Output Mixer 0 = Disable (Mute) 1 = Enable Path RINPUT3 to Right Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Reserved Reserved Left Output Mixer to Mono Output Mixer Control 0 = Left channel mix disabled 1 = Left channel mix enabled Reserved Reserved Right Output Mixer to Mono Output Mixer Control 0 = Right channel mix disabled 1 = Right channel mix enabled Reserved Speaker Volume Update Writing a 1 to this bit will cause left and right speaker volumes to be updated (SPKLVOL and SPKRVOL) Left Speaker Zero Cross Enable 1 = Change gain on zero cross only 0 = Change gain immediately SPK_LP/SPK_LN Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Speaker Volume Update Writing a 1 to this bit will cause left and right speaker volumes to be updated (SPKLVOL and SPKRVOL) Right Speaker Zero Cross Enable 1 = Change gain on zero cross only 0 = Change gain immediately SPK_RP/SPK_RN Volume 1111111 = +6dB ... 1dB steps down to 0110000 = -73dB 0101111 to 0000000 = Analogue MUTE Reserved
WM8956
REFER TO Output Signal Path
3:0 R35 (23h) R36 (24h) R37 (25h) Right Out Mix 8:0 8:0 8 RD2RO
0000 001010000 001010000 0
Output Signal Path Output Signal Path Output Signal Path
7
RI2RO
0
6:4
RI2ROVOL[2:0]
101
3:0 R38 (26h) Mono Out Mix (1) 8 7 L2MO
0000 0 0
Output Signal Path
6:0 R39 (27h) Mono Out Mix (2) 8 7 R2MO
0000000 0 0
Output Signal Path
6:0 R40 (28h) Left Speaker Volume 8 SPKVU
0000000 N/A
Analogue Outputs
7
SPKLZC
0
Analogue Outputs Analogue Outputs
6:0
SPKLVOL[6:0]
0000000
R41 (29h) Right Speaker Volume
8
SPKVU
N/A
Analogue Outputs
7
SPKRZC
0
Analogue Outputs Analogue Outputs
6:0
SPKRVOL[6:0]
0000000
R42 (2Ah)
8:7
00
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WM8956
REGISTER ADDRESS OUT3 Volume BIT 6 LABEL MOUTVOL 1 DEFAULT DESCRIPTION Mono Output Mixer Volume Control 0 = 0dB 1 = -6dB Reserved Reserved LINPUT3 to Boost Mixer Gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB LINPUT2 to Boost Mixer Gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB Reserved Reserved RINPUT3 to Boost Mixer Gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB RINPUT2 to Boost Mixer Gain 000 = Mute 001 = -12dB ...3dB steps up to 111 = +6dB Reserved Reserved Left Input Boost Mixer to Left Output Mixer 0 = Disable (Mute) 1 = Enable Path Left Input Boost Mixer to Left Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Reserved Reserved
Preliminary Technical Data REFER TO Output Signal Path
5:0 R43 (2Bh) Left Input Boost Mixer 8:7 6:4 LIN3BOOST[2:0]
000000 00 000
Input Signal Path
3:1
LIN2BOOST[2:0]
000
Input Signal Path
0 R44 (2Ch) Right Input Boost Mixer 8:7 6:4 RIN3BOOST[2:0]
0 00 000
Input Signal Path
3:1
RIN2BOOST[2:0]
000
Input Signal Path
0 R45 (2Dh) Left Bypass 8 7 LB2LO
0 0 0
Output Signal Path Output Signal Path
6:4
LB2LOVOL[2:0]
101
3:0 R46 (2Eh) Right Bypass 8 7 RB2RO
0000 0 0
Right Input Boost Mixer to Right Output Mixer 0 = Disable (Mute) 1 = Enable Path Right Input Boost Mixer to Right Output Mixer Volume 000 = 0dB ...(3dB steps) 111 = -21dB Reserved Reserved Left Channel Input PGA Enable 0 = PGA disabled 1 = PGA enabled (if AINL = 1)
Output Signal Path Output Signal Path
6:4
RB2ROVOL[2:0]
101
3:0 R47 (2Fh) Power Mgmt (3) 8:6 5 LMIC
0000 000 0
Input Signal Path
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Preliminary Technical Data REGISTER ADDRESS BIT 4 RMIC LABEL 0 DEFAULT DESCRIPTION Right Channel Input PGA Enable 0 = PGA disabled 1 = PGA enabled (if AINR = 1) Left Output Mixer Enable Control 0 = Disabled 1 = Enabled Right Output Mixer Enable Control 0 = Disabled 1 = Enabled Reserved Reserved GPIO Polarity Invert 0 = Non inverted 1 = Inverted GPIO1 GPIO Function Select: 000 = Jack detect input 001 = Reserved 010 = Temperature ok 011 = Debounced jack detect output 100 = SYSCLK output 101 = PLL lock 110 = Logic 0 111 = Logic 1 Headphone Switch Input Select 0X = GPIO1 used for jack detect input (Requires pin to be configured as a GPIO using ALRCGPIO) 10 = JD2 used for jack detect input 11 = JD3 used for jack detect input Temperature Sensor Enable 0 = Temperature sensor disabled 1 = Temperature sensor enabled Microphone Bias Voltage Control 0 = 0.9 * AVDD 1 = 0.65 * AVDD Reserved Enable Class D Speaker Outputs 00 = Off 01 = Left speaker only 10 = Right speaker only 11 = Left and right speakers enabled Reserved Reserved Reserved DC Speaker Boost (Boosts speaker DC output level by up to 1.8 x on left and right channels) 000 = 1.00x boost (+0dB) 001 = 1.27x boost (+2.1dB) 010 = 1.40x boost (+2.9dB) 011 = 1.52x boost (+3.6dB) 100 = 1.67x boost (+4.5dB) 101 = 1.8x boost (+5.1dB) 110 to 111 = Reserved
WM8956
REFER TO Input Signal Path Output Signal Path Output Signal Path
3
LOMIX
0
2
ROMIX
0
1:0 R48 (30h) Additional Control (4) 8 7 GPIOPOL
00 0 0
General Purpose Input / Output General Purpose Input / Output
6:4
GPIOSEL[2:0]
000
3:2
HPSEL[1:0]
00
Headphone Jack Detect
1
TSENSEN
1
Thermal Shutdown Input Signal Path
0
MBSEL
0
R49 (31h) Class D Control (1)
8 7:6 SPK_OP_EN[1:0]
0 00
Enabling the Outputs
5:0 R50 (32h) R51 (33h) Class D Control (2) 8:0 8:6 5:3 DCGAIN[2:0]
110111 001001101 010 000
Analogue Outputs
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WM8956
REGISTER ADDRESS BIT 2:0 LABEL ACGAIN[2:0] DEFAULT 000 DESCRIPTION
Preliminary Technical Data REFER TO Analogue Outputs
AC Speaker Boost (Boosts speaker AC output signal by up to 1.8 x on left and right channels) 000 = 1.00x boost (+0dB) 001 = 1.27x boost (+2.1dB) 010 = 1.40x boost (+2.9dB) 011 = 1.52x boost (+3.6dB) 100 = 1.67x boost (+4.5dB) 101 = 1.8x boost (+5.1dB) 110 to 111 = Reserved SYSCLK Output to GPIO Clock Division ratio 000 = SYSCLK 001 = SYSCLK / 2 010 = SYSCLK / 3 011 = SYSCLK / 4 100 = SYSCLK / 5.5 101 = SYSCLK / 6 Enable Integer Mode 0 = Integer mode 1 = Fractional mode Divide MCLK by 2 before input to PLL 0 = Divide by 1 1 = Divide by 2 Integer (N) part of PLL input/output frequency ratio. Use values greater than 5 and less than 13. Reserved Fractional (K) part of PLL1 input/output frequency ratio (treat as one 24-digit binary number). Reserved Fractional (K) part of PLL1 input/output frequency ratio (treat as one 24-digit binary number). Reserved Fractional (K) part of PLL1 input/output frequency ratio (treat as one 24-digit binary number).
R52 (34h) PLL (1)
8:6
OPCLKDIV[2:0]
000
General Purpose Input / Output
5
SDM
0
Clocking and Sample Rates Clocking and Sample Rates Clocking and Sample Rates
4
PLLPRESCALE
0
3:0
PLLN[3:0]
1000
R53 (35h) PLL (2)
8 7:0 PLLK[23:16]
0 00110001
Clocking and Sample Rates
R54 (36h) PLL (3)
8 7:0 PLLK[15:8]
0 00100110
Clocking and Sample Rates
R55 (37h) PLL (4)
8 7:0 PLLK[7:0]
0 11101001
Clocking and Sample Rates
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Preliminary Technical Data
WM8956
DIGITAL FILTER CHARACTERISTICS
PARAMETER DAC Normal Filter Passband Passband Ripple Stopband Stopband Attenuation DAC Sloping Stopband Filter Passband +/- 0.03dB +/- 1dB -6dB Passband Ripple Stopband 1 Stopband 1 Attenuation Stopband 2 Stopband 2 Attenuation Stopband 3 Stopband 3 Attenuation f > 1.4 fs f > 0.7 fs f > 0.546 fs 0.25 fs 0.546 fs -60 0.7 fs -85 1.4 fs -55 dB 1.4 fs dB 0 0.25 fs 0.5 fs +/- 0.03 0.7 fs dB dB 0.25 fs 0.454 fs f > 0.546 fs +/- 0.03dB -6dB 0.454 fs 0.546 fs -50 dB 0 0.5 fs +/- 0.03 dB 0.454 fs TEST CONDITIONS MIN TYP MAX UNIT
DAC FILTERS Mode Normal Sloping Stopband Group Delay 18 / fs 18 / fs
DAC FILTER RESPONSES
DAC STOPBAND ATTENUATION
The DAC digital filter type is selected by the DACSLOPE register bit as shown in Table 42. REGISTER ADDRESS R6 (06h) DAC Control (2) BIT 1 LABEL DACSLOPE DEFAULT 0 DESCRIPTION Selects DAC filter characteristics 0 = Normal mode 1 = Sloping stopband mode
Table 42 DAC Filter Selection
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WM8956
MAGNITUDE(dB) 10 -10 0 -30 -50
0.02 0.04 MAGNITUDE(dB)
Preliminary Technical Data
0.5
1
1.5
2
2.5
3
0.035 0.03 0.025
-70 -90 -110 -130 -150 Frequency (fs)
0.015 0.01 0.005 0 -0.005 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Frequency (fs)
Figure 36 DAC Digital Filter Frequency Response (Normal Mode)
MAGNITUDE(dB) 10 -10 0 -30 -50 -70 -90 -110 -130 -150 Frequency (fs) 0.5 1 1.5 2 2.5 3
Figure 37 DAC Digital Filter Ripple (Normal Mode)
MAGNITUDE(dB) 0.05 0 -0.05 -0.1 -0.15 -0.2 -0.25 -0.3 -0.35 -0.4 -0.45 -0.5 Frequency (fs) 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Figure 38 DAC Digital Filter Frequency Response (Sloping Stopband Mode)
Figure 39 DAC Digital Filter Ripple (Sloping Stopband Mode)
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Preliminary Technical Data
WM8956
DE-EMPHASIS FILTER RESPONSES
MAGNITUDE(dB)
0.3 MAGNITUDE(dB)
0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 Frequency (Hz) 0 5000 10000 15000 20000
0.25 0.2 0.15 0.1 0.05 0 -0.05 -0.1 -0.15 Frequency (Hz) 0 2000 4000 6000 8000 10000 12000 14000 16000 18000
Figure 40 De-Emhpasis Digital Filter Response (32kHz)
Figure 41 De-Emphasis Error (32kHz)
MAGNITUDE(dB) 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 Frequency (Hz) 0 5000 10000 15000 20000 25000
MAGNITUDE(dB) 0.2 0.15 0.1 0.05 0 0 -0.05 -0.1 Frequency (Hz) 5000 10000 15000 20000 25000
Figure 42 De-Emhpasis Digital Filter Response (44.1kHz)
Figure 43 De-Emphasis Error (44.1kHz)
MAGNITUDE(dB) 0 0 -2 -4 -6 -8 -10 -12 Frequency (Hz) 5000 10000 15000 20000 25000 30000
0.1 0.15
MAGNITUDE(dB)
0.05 0 0 -0.05 5000 10000 15000 20000 25000 30000
-0.1 -0.15 Frequency (Hz)
Figure 44 De-Emhpasis Digital Filter Response (48kHz)
Figure 45 De-Emphasis Error (48kHz)
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WM8956 APPLICATIONS INFORMATION
RECOMMENDED EXTERNAL COMPONENTS
Preliminary Technical Data
SPEAKER SELECTION
For filterless operation, it is important to select a speaker with appropriate internal inductance. The internal inductance and the speaker's load resistance create a low-pass filter with a cut-off frequency of: fc = RL / 2L e.g. for an 8 speaker and required cut-off frequency of 20kHz, the speaker should be chosen to have an inductance of: L = RL / 2fc = 8 / 2 * 20kHz = 64H 8 speakers typically have an inductance in the range 20H to 100H. Care should be taken to ensure that the cut-off frequency of the speaker's internal filtering is low enough to prevent speaker damage. The class D outputs of the WM8956 operate at much higher frequencies than is recommended for most speakers, and the cut-off frequency of the filter should be low enough to protect the speaker.
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Preliminary Technical Data
WM8956
Figure 46 Speaker Equivalent Circuit
PCB LAYOUT CONSIDERATIONS
The efficiency of the speaker drivers is affected by the series resistance between the WM8956 and the speaker (e.g. inductor ESR) as shown in Figure 47. This resistance should be as low as possible to maximise efficiency.
VDD
Class D output Switching Losses
VMID
GND
Losses due to resistance between WM8956 and speaker (e.g. inductor ESR) This resistance must be minimised in order to maximise efficiency.
Figure 47 Speaker Connection Losses The distance between the WM8956 and the speakers should be kept to a minimum to reduce series resistance, and also to reduce EMI. Further reductions in EMI can be achieved by additional passive filtering and/or shielding as shown in Figure 48. When additional passive filtering is used, low ESR components should be chosen to minimise series resistance between the WM8956 and the speaker, maximising efficiency. LC passive filtering will usually be effective at reducing EMI at frequencies up to around 30MHz. To reduce emissions at higher frequencies, ferrite beads placed as close to the device as possible will be more effective.
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WM8956
Preliminary Technical Data
Figure 48 EMI Reduction Techniques
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Preliminary Technical Data
WM8956
PACKAGE DRAWING
FL: 32 PIN QFN PLASTIC PACKAGE 5 X 5 X 0.9 mm BODY, 0.50 mm LEAD PITCH DM033.D
D
D2 25 32 L 24 EXPOSED GROUND 6 PADDLE A 1
DETAIL 1
4
INDEX AREA (D/2 X E/2)
E2
E
17
8 2X 9 B b 1 bbb M C A B 2X aaa C aaa C
16 e
15
BOTTOM VIEW
ccc C A3 A 0.08 C 5
TOP VIEW
R = 0.3MM EXPOSED GROUND PADDLE
C
SEATING PLANE
SIDE VIEW
A1
DETAIL 2
W T
A3 H b Exposed lead
G
DETAIL 1
Half etch tie bar
DETAIL 2
Symbols A A1 A3 b D D2 E E2 e G H L T W MIN 0.80 0 0.18 3.30 3.30
Dimensions (mm) NOM MAX NOTE 0.90 1.00 0.02 0.05 0.20 REF 1 0.25 0.30 5.00 3.45 5.00 3.45 0.50 BSC 0.213 0.1 0.40 0.1 0.2 3.55 3.55 2 2
0.30
0.50
Tolerances of Form and Position aaa bbb ccc REF: 0.15 0.10 0.10 JEDEC, MO-220, VARIATION VHHD-5.
NOTES: 1. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.15 mm AND 0.30 mm FROM TERMINAL TIP. 2. FALLS WITHIN JEDEC, MO-220, VARIATION VHHD-5. 3. ALL DIMENSIONS ARE IN MILLIMETRES. 4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JEDEC 95-1 SPP-002. 5. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS. 6. REFER TO APPLICATION NOTE WAN_0118 FOR FURTHER INFORMATION REGARDING PCB FOOTPRINTS AND QFN PACKAGE SOLDERING. 7. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
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WM8956 IMPORTANT NOTICE
Preliminary Technical Data
Wolfson Microelectronics plc ("Wolfson") products and services are sold subject to Wolfson's terms and conditions of sale, delivery and payment supplied at the time of order acknowledgement.
Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson reserves the right to make changes to its products and specifications or to discontinue any product or service without notice. Customers should therefore obtain the latest version of relevant information from Wolfson to verify that the information is current.
Testing and other quality control techniques are utilised to the extent Wolfson deems necessary to support its warranty. Specific testing of all parameters of each device is not necessarily performed unless required by law or regulation.
In order to minimise risks associated with customer applications, the customer must use adequate design and operating safeguards to minimise inherent or procedural hazards. Wolfson is not liable for applications assistance or customer product design. The customer is solely responsible for its selection and use of Wolfson products. Wolfson is not liable for such selection or use nor for use of any circuitry other than circuitry entirely embodied in a Wolfson product.
Wolfson's products are not intended for use in life support systems, appliances, nuclear systems or systems where malfunction can reasonably be expected to result in personal injury, death or severe property or environmental damage. Any use of products by the customer for such purposes is at the customer's own risk.
Wolfson does not grant any licence (express or implied) under any patent right, copyright, mask work right or other intellectual property right of Wolfson covering or relating to any combination, machine, or process in which its products or services might be or are used. Any provision or publication of any third party's products or services does not constitute Wolfson's approval, licence, warranty or endorsement thereof. Any third party trade marks contained in this document belong to the respective third party owner.
Reproduction of information from Wolfson datasheets is permissible only if reproduction is without alteration and is accompanied by all associated copyright, proprietary and other notices (including this notice) and conditions. Wolfson is not liable for any unauthorised alteration of such information or for any reliance placed thereon.
Any representations made, warranties given, and/or liabilities accepted by any person which differ from those contained in this datasheet or in Wolfson's standard terms and conditions of sale, delivery and payment are made, given and/or accepted at that person's own risk. Wolfson is not liable for any such representations, warranties or liabilities or for any reliance placed thereon by any person.
ADDRESS:
Wolfson Microelectronics plc 26 Westfield Road Edinburgh EH11 2QB United Kingdom
Tel :: +44 (0)131 272 7000 Fax :: +44 (0)131 272 7001 Email :: sales@wolfsonmicro.com
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