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19-3490; Rev 0; 11/04
Stereo Audio Taper Potentiometers with Pushbutton Interface
General Description
The MAX5456/MAX5457 dual, logarithmic taper digital potentiometers feature a simple pushbutton interface that controls volume and balance in audio applications. Each potentiometer has 32 tap points and replaces mechanical potentiometers. Refer to the MAX5408- MAX5411 data sheet for SPITM versions of the MAX5456/ MAX5457. Use the MAX5456/MAX5457 digital inputs with momentary contact single-pole/single-throw (SPST) pushbutton switches. Each input includes internal debounce circuitry and a 50k pullup resistor. The MAX5456/MAX5457 advance the wiper setting once per button push. Maxim's proprietary SmartWiperTM control eliminates the need for a microcomputer to increase the wiper transition rate. Holding the control input low for more than 1s advances the wiper at a rate of 4Hz for 4s and 16Hz per second thereafter. The MAX5456/MAX5457 provide temperature coefficients of 50ppm/C end-to-end and 5ppm/C ratiometric and a nominal resistance of 10k per potentiometer. An integrated click/pop suppression feature minimizes the audible noise generated by wiper transitions. The typical total harmonic distortion plus noise (THD+N) for these devices is 0.01%. The MAX5457 features a 3-button interface with a MODE input that toggles between volume- and balancecontrol modes. An LED output indicates volume or balance mode. The MAX5456 features a 4-button interface with separate inputs for up and down volume controls and left and right balance controls. The MAX5456/MAX5457 are available in 16-pin QSOP and 16-pin TQFN packages and are specified over the extended (-40C to +85C) temperature range.
Features
SmartWiper Control Provides Accelerated Wiper Motion Debounced Pushbutton Interface with Internal Pullup Resistors Logarithmic Taper with 2dB Steps Between Taps Single +2.7V to +5.5V or Dual 2.7V Supply Operation Low 0.5A Standby Supply Current Clickless Switching 10k End-to-End Fixed Resistance Value Mute Function to -90dB (typ) Power-On Reset to -12dB Wiper Position 32 Tap Positions for Each Wiper Small 16-Pin QSOP/TQFN Packages
MAX5456/MAX5457
Ordering Information
PART MAX5456EEE MAX5456ETE* MAX5457EEE* MAX5457ETE* TEMP RANGE -40 C to +85 C -40oC to +85oC -40 C to +85 C -40oC to +85oC
o o o o
PIN-PACKAGE 16 QSOP 16 TQFN 16 QSOP 16 TQFN
*Future product--contact factory for availability.
Pin Configurations
TOP VIEW
DN/BAL0 1 16 VDD 15 VLOGIC 14 GND
Applications
Stereo Volume Control Fading and Balancing Stereo Signals Stereo Blending and Mixing
Typical Application Circuits and Selector Guide appear at end of data sheet.
UP/BAL1 2 MODE 3 MODE_IND 4 H0 5 L0 6 W0 7 SHDN 8
MAX5457
13 VSS 12 H1 11 L1 10 W1 9 MUTE
SPI is a trademark of Motorola, Inc. SmartWiper is a trademark of Maxim Integrated Products, Inc.
QSOP Pin Configurations are continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
ABSOLUTE MAXIMUM RATINGS
(MAX5456) SHDN, MUTE, VOLUP, VOLDN, BAL_ to GND.....................................-0.3V to (VLOGIC + 0.3V) (MAX5457) SHDN, MUTE, UP/BAL1, DN/BAL0, MODE, MODE_IND to GND...........................-0.3V to (VLOGIC + 0.3V) H_, L_, and W_ to VSS ..............................-0.3V to (VDD + 0.3 V) VDD to GND ..............................................................-0.3V to +6V VDD to VSS ................................................................-0.3V to +6V VLOGIC to GND.........................................................-0.3V to +6V VLOGIC to VSS ...........................................................-0.3V to +6V VSS to GND............................................................-3.0V to +0.3V Peak Current into H_, L_, and W_.......................................1mA Average Current into H_, L_, and W_ ..............................500A Input and Output Latchup Immunity...............................200mA Continuous Power Dissipation (TA = +70C) 16-Pin QSOP (derate 8.3mW/C above +70C)........666.7mW 16-Pin TQFN (derate 16.9mW/C above +70C) ....1349.1mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-60C to +150C Lead Temperature (soldering, 10s) .................................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise specified.) (Note 1)
PARAMETER End-to-End Resistance Maximum Bandwidth Absolute Ratio Tolerance Tap-to-Tap Tolerance VDD = 5V, VH_ = (VDD / 2) + 1VRMS, f = 1kHz, tap = -6dB, VL_ = VDD / 2, RL = Total Harmonic Distortion Plus Noise THD+N VDD = 3V, VSS = 0V, VL_ = 1.5V, VH_ = 1.5V + 1VRMS, f = 1kHz, RL = 10k to (VDD / 2), CL = 5pF, tap = -6dB f = 20Hz to 20kHz, tap = -6dB PSRR RW CW CH CL SYMBOL R fCUTOFF Figures 1, 2 From H_ to W_, CLOAD = 10pF No load at the output of the wiper, W_ = -6dB CONDITIONS MIN 7 TYP 10 100 0.25 0.1 0.01 % 0.23 -100 0.5 -90 -80 1000 10 5 7 50 5 en RPULLUP tlPW tHPW tWS Figure 5 Figure 5 Click/pop suppression inactive 20Hz to 20kHz 32 22.5 40 32 0.95 50 65 1700 dB dB dB dB pF pF pF ppm/C ppm/C VRMS k ms ms ms MAX 13 UNITS k kHz dB dB
Channel-to-Channel Isolation Interchannel Matching Mute Attenuation Power-Supply Rejection Ratio Wiper Resistance Wiper Capacitance H Terminal Capacitance L Terminal Capacitance End-to-End Resistance Temperature Coefficient Ratiometric Resistance Temperature Coefficient Output Noise Internal Pullup Resistor Single Pulse-Width Input Repetitive Input Pulse High Time Timeout Period PUSHBUTTON CONTACT INPUTS (UP/BAL1, DN/BAL0, MUTE, VOLUP, VOLDN, BAL0, BAL1, MODE)
2
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Stereo Audio Taper Potentiometers with Pushbutton Interface
ELECTRICAL CHARACTERISTICS (continued)
(VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise specified.) (Note 1)
PARAMETER First Autoincrement Point First Autoincrement Rate Second Autoincrement Point Second Autoincrement Rate DIGITAL INPUTS (VLOGIC > 4.5V) Input High Voltage Input Low Voltage Input Leakage Current Input Capacitance DIGITAL INPUTS (VLOGIC < 4.5V) Input High Voltage Input Low Voltage Input Leakage Current Input Capacitance POWER SUPPLIES Supply Voltage Negative Power Supply Supply-Voltage Difference Active Supply Current Standby Supply Current Shutdown Supply Current Power-Up Time Logic Standby Voltage Logic Active Supply Current Logic Standby Supply Current Logic Shutdown Current DIGITAL OUTPUT, MODE_IND Output Low Voltage Output Leakage Current Output Capacitance Maximum Sink Current VOL VLOGIC = 2.7V, ISINK = 10mA VLOGIC = 5.5V, ISINK = 10mA 0.1 3 150 0.4 0.2 10 V A pF mA IDD ISTBY ISHDN tPU VLOGIC ILOGIC ILOGICSTBY (Note 2) (Note 3) 0.5 2.7 VDD VSS VDD - VSS (Note 2) VDD = +5.5V, VSS = 0V, VLOGIC = 2.7V (Note 3) VLOGIC = VDD = +2.7V, VSS = -2.7V (Note 3) (Note 4) 10 VDD 160 1 1 2 0.5 2.7 -2.7 5.5 0 5.5 100 10 1 1 V V V A A A ms V A A A VIH VIL Inputs floating 5 0.7 x VLOGIC 0.3 x VLOGIC 1 V V A pF VIH VIL Inputs floating 5 2.4 0.8 1 V V A pF SYMBOL CONDITIONS MIN TYP 1 4 4 16 MAX UNITS s Hz s Hz
MAX5456/MAX5457
ILOGICSHDN (Note 4)
Note 1: Parameters are 100% production tested at +85C and limits through temperature are guaranteed by design. Note 2: Supply current measured with the supply on and a button pushed. Note 3: Supply current measured with the power on, no button pushed, and the wiper position fixed. Note 4: This is the measured current with SHDN low and MODE_IND unconnected.
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Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Typical Operating Characteristics
(VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise specified.)
WIPER RESISTANCE vs. WIPER VOLTAGE
VDD = VLOGIC = 5V
MAX5456/7 toc01
ATTENUATION vs. TAP POSITION
MAX5456/7 toc02
END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE
END-TO-END RESISTANCE CHANGE (%) 0.4 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 -40 -15 10 35 60 85
MAX5456/7 tpc03
1200 1150 1100 WIPER RESISTANCE () 1050 1000 950 900 850 800 750 700 650 600
0 -10 ATTENUATION (dB) -20 -30 -40 -50 -60 -70
0.5
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V)
0
4
8
12
16
20
24
28
32
TAP POSITION
TEMPERATURE (C)
ACTIVE SUPPLY CURRENT vs. TEMPERATURE
215 ACTIVE SUPPLY CURRENT (A) 210 205 200 195 190 185 180 -40 -15 10 35 60 85 1V/div VDD = VLOGIC = 5.5V, ILOGIC + IVDD
MAX5456/7 toc04
WIPER SWITCHING TRANSIENT (TIMING OUT)
MAX5456/7 toc05a
220
5V/div
VH_ = VDD VL_ = 0
VOLUP
WIPER TRANSITION FROM -2dB to 0dB
10ms/div
TEMPERATURE (C)
WIPER SWITCHING TRANSIENT (SUPPRESSION CIRCUIT ACTIVE)
MAX5456/7 toc05b
LOGIC SUPPLY CURRENT vs. LOGIC SUPPLY VOLTAGE
180 LOGIC SUPPLY CURRENT (A)
MAX5456/7 toc06a
200 VOLUP
5V/div VH_ = SQUARE WAVE FROM VDD TO VSS, VL_ = VDD / 2 2V/div
160 140 120 100 80 60 40 20 0 ACTIVE LOGIC SUPPLY CURRENT
WIPER TRANSITION FROM -2dB to 0dB
4ms/div
2.7
3.2
3.7
4.2
4.7
5.2 5.5
LOGIC SUPPLY VOLTAGE (V)
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Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Typical Operating Characteristics (continued)
(VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise specified.)
LOGIC SUPPLY CURRENT vs. LOGIC SUPPLY VOLTAGE
MAX5456/7 toc06b
WIPER-TO-END TERMINAL RESISTANCE vs. TAP POSITION
MAX5456/7 toc07
FREQUENCY RESPONSE
2 0 RESPONSE (dB) W_ SET TO 0dB -2 -4 W_ SET TO -6dB -6 -8 VH_ = 2.5V 1VP-P, VL_ = 2.5V, CL_ = 10pF
MAX5456/7 toc08
0.30 0.25 0.20 0.15 0.10 0.05 0 2.7 3.2 3.7 4.2 4.7 STANDBY LOGIC SUPPLY CURRENT
100 NOMINAL END-TO-END RESISTANCE (%RHL) RWH 75
LOGIC SUPPLY CURRENT (A)
50
25 RWL 0
5.2 5.5
0
8
16 TAP POSITION
24
32
0.01
0.1
1
10
100
1000
LOGIC SUPPLY VOLTAGE (V)
FREQUENCY (kHz)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
VH_ = 2.5V 1VP-P, VL_ = 2.5V, W_ SET TO -6dB, 20Hz TO 20kHz BANDPASS
MAX5456/7 toc09
DIGITAL SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE
MAX5456/7 toc10
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
-10 -20 -30 PSRR (dB) -40 -50 -60 -70 -80 -90 VDD = 5V 1VP-P, VH_ = 5V, VL_ = 2.5V, W_ SET TO -6dB
MAX5456/7 toc11
100 10 1 THD+N (%) 0.1 0.01
1000 900 DIGITAL SUPPLY CURRENT (A) 800 700 600 500 400 300 200 100
0
LOAD = 10k
NO LOAD 0.001 0.0001 10 100 1000 FREQUENCY (Hz) 10,000 100,000
0 0 1 2 3 4 5 DIGITAL INPUT VOLTAGE (V)
1
10
100
1000
FREQUENCY (kHz)
LOGIC SUPPLY CURRENT vs. TEMPERATURE
MAX5456/7 toc12
SPECTRAL NOISE DENSITY
9 8 NOISE (nVRMS/Hz) 7 6 5 4 3 2 1 0
MAX5456 toc13
150 149 LOGIC SUPPLY CURRENT (mA) 148 147 146 145 144 143 142 141 140 -40 -15 10 35 60 ACTIVE LOGIC SUPPLY CURRENT VLOGIC = 5.5V
10
85
0.01
0.1
1 FREQUENCY (kHz)
10
100
TEMPERATURE (C)
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Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Pin Description
PIN MAX5457 TQFN 1 QSOP 3 MAX5456 TQFN -- QSOP -- MODE Volume/Balance Control. Each transition from high to low toggles between volume and balance modes. MODE is pulled high internally with a 50k resistor to VLOGIC. On power-up, the MAX5457 is in volume-control mode. NAME FUNCTION
2
4
--
--
Volume-Control/Balance-Control Mode Indicator Open-Drain Output. Connect to an LED through a resistor to VLOGIC. When the LED is on, the MAX5457 is in MODE_IND balance-control mode. When the LED is off, the MAX5457 is in volume-control mode. See the Mode Indicator, MODE_IND section for more detail. H0 L0 W0 Potentiometer 0 High Terminal. H0 and L0 terminals can be reversed. Potentiometer 0 Low Terminal. L0 and H0 terminals can be reversed. Potentiometer 0 Wiper Terminal Active-Low Shutdown Input. In shutdown mode, the MAX5456/MAX5457 store the last wiper settings. The wipers move to the L end of the resistor string, and the H end of the resistor string disconnects from the signal input. Terminating shutdown mode restores the wipers to their previous settings. Mute Input. When MUTE is low, the wiper goes to the highest attenuation setting (see Table 1). MUTE is internally pulled up with 50k to VLOGIC. Potentiometer 1 Wiper Terminal Potentiometer 1 Low Terminal. L1 and H1 terminals can be reversed. Potentiometer 1 High Terminal. H1 and L1 terminals can be reversed. Negative Power Supply. Bypass with 0.1F to ground. Ground Digital Logic Power Supply. Bypass with 0.1F to ground. Analog Power Supply. Bypass with 0.1F to ground. Downward Volume/Channel 0 Balance-Control Input. In volume mode, pressing DN/BAL0 moves both wipers towards the L terminals. In balance mode, pressing DN/BAL0 moves the balance towards channel 0. DN/BAL0 is internally pulled up with 50k to VLOGIC. Upward Volume/Channel 1 Balance-Control Input. In volume mode, pressing UP/BAL1 moves both wipers towards the H terminals. In balance mode, pressing UP/BAL1 moves the balance towards channel 1. UP/BAL1 is internally pulled up with 50k to VLOGIC. Channel 1 Balance-Control Input. Pressing BAL1 moves the balance towards channel 1. BAL1 is internally pulled up with 50k to VLOGIC. Channel 0 Balance-Control Input. Pressing BAL0 moves the balance towards channel 0. BAL0 is internally pulled up with 50k to VLOGIC. Downward Volume-Control Input. Pressing VOLDN moves both wipers towards the L terminals. VOLDN is internally pulled up with 50k to VLOGIC. Upward Volume-Control Input. Pressing VOLUP moves both wipers towards the H terminals. VOLUP is internally pulled up with 50k to VLOGIC.
3 4 5
5 6 7
3 4 5
5 6 7
6
8
6
8
SHDN
7 8 9 10 11 12 13 14
9 10 11 12 13 14 15 16
7 8 9 10 11 12 13 14
9 10 11 12 13 14 15 16
MUTE W1 L1 H1 VSS GND VLOGIC VDD
15
1
--
--
DN/BAL0
16
2
--
--
UP/BAL1
-- -- -- --
-- -- -- --
1 2 15 16
3 4 1 2
BAL1 BAL0 VOLDN VOLUP
6
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Stereo Audio Taper Potentiometers with Pushbutton Interface
Detailed Description
The MAX5456/MAX5457 dual, logarithmic taper digital potentiometers feature a simple pushbutton interface that controls volume and balance in audio applications. Each potentiometer has 32 tap points and replaces mechanical potentiometers (see the Functional Diagrams).
MAX5456 MAX5457
CH RW W_ CW L_ CL R
MAX5456/MAX5457
H_
Up and Down Interface
The MAX5456/MAX5457 interface with momentary contact SPST switches. All switch inputs are internally debounced and pulled up to V LOGIC through 50k resistors. The wiper setting advances once per button press up to 1s. Maxim's SmartWiper control circuitry allows the wiper to advance at a rate of 4Hz when an input is held low from 1s up to 4s, and at a rate of 16Hz if the contact is maintained for greater than 4s (see Table 2). The SmartWiper control eliminates the need for a microcomputer to increase the wiper transition rate. The MAX5456 features independent control inputs for volume and balance control while the MAX5457 MODE input toggles between volume and balance control. Each transition of MODE from high to low toggles the MAX5457 between volume-control and balance-control modes. MODE is internally pulled high with a 50k resistor to VLOGIC. Volume Control In volume-control mode, the MAX5456/MAX5457s' wipers move simultaneously, maintaining the balance separation between each wiper (Figure 3a). When either wiper reaches the maximum tap position (position closest to H_), further commands to increase the volume are ignored. Balance separation is maintained in the maximum volume configuration (Figure 3b). When either wiper reaches the minimum tap position (position closest to L_), further commands to decrease the volume adjust the other wiper until it also reaches the minimum tap position (Figure 3c). Increasing the volume from this minimum position restores the original balance separation of the wipers (Figure 3d). When both wipers are in the 31st tap position (-62dB attenuation), further commands to VOLDN place the wipers in the mute position (see Table 1). VOLUP or MUTE pulses return wipers to position 31.
Figure 1. Potentiometer Model (Active)
MAX5456 MAX5457
CH R RW W_ CW CL
H_
L_
Figure 2. Potentiometer Model (Shutdown)
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Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
H_ W0 W1 PRESS VOLUP TWICE W0 W1 PRESS VOLDN ONCE BALANCE SEPARATION MAINTAINED W0 W1
(a)
L_ NO CHANGE W0 H_ W1 PRESS VOLUP ONCE W0 W1 PRESS VOLUP W0 W1
(b)
L_ H_ W0 W1 PRESS VOLDN ONCE W0 W1 PRESS VOLDN TO 3d (c) W0 W1
L_
H_ W0 FROM 3c (d) W1 PRESS VOLUP ONCE W0 W1 PRESS VOLUP ONCE
ORIGINAL BALANCE SEPARATION MAINTAINED W0 W1
L_
Figure 3. Volume-Control Operation
Table 1. Wiper Position and Attenuation
POSITION 0 1 2 6 (POR) 30 31 32 (mute) ... ... ATTENUATION (dB) 0 2 4 12 60 62 >90 ... ...
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Stereo Audio Taper Potentiometers with Pushbutton Interface
Balance Control In balance-control mode, the MAX5456/MAX5457 adjust the balance between channel 0 and channel 1 while maintaining the set volume. For example, if the volume of channel 0 equals the volume of channel 1, forcing the balance towards channel 1 increases the attenuation of channel 0 (Figure 4a). If channel 1 is at a higher attenuation than channel 0, adjusting the balance to channel 1 moves channel 1's wiper up to the same wiper position as channel 0 before attenuating channel 0 (Figure 4b). To control the wiper quickly with a logic signal, maintain pulses at least 22.5ms wide and separated by at least 40ms.
Table 2. Wiper Action vs. Pushbutton Contact Duration
CONTACT DURATION t < 22.5ms 22.5ms < t 1s 1s < t 4s t > 4s WIPER ACTION No motion (debouncing). Wiper changes position once. Wiper changes position at a rate of 4Hz. Wiper changes position at a rate of 16Hz.
MAX5456/MAX5457
H_
VOLUME LEVEL IS SET W0 W1 PRESS BAL1 ONCE W0 W1 PRESS BAL1 ONCE
VOLUME LEVEL MAINTAINED BALANCE SHIFTS TO W1 W0 W1
(a)
L_ H_ VOLUME LEVEL IS SET BY W0 W0 W1 PRESS BAL1 ONCE W0 W1 PRESS BAL1 ONCE
VOLUME LEVEL MAINTAINED BALANCE SHIFTS TO W1 W0 W1
(b)
L_
Figure 4. Balance-Control Operation
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Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Click/Pop Suppression
The click/pop suppression feature reduces the audible noise (clicks and pops) that result from wiper transitions. The MAX5456/MAX5457 minimize this noise by allowing the wiper position changes only when VH_ = VL_. Thus, the wiper changes position only when the voltage at L_ is the same as the voltage at the corresponding H_. Each wiper has its own suppression and timeout circuitry (see Figure 5a). The MAX5456/MAX5457 change wiper position after 32ms or when VH_ = VL, whichever occurs first (see Figure 5b). The suppression circuitry monitors left and right channels separately. In volume-control mode, when the first wiper changes position, the second wiper has 32ms to change or it will be forced to change.
Power-On Reset
The power-on comparators monitor V DD - V SS and VLOGIC - GND. A power-on reset is initiated when either of the supplies is brought back to normal operating voltage. The power-on-reset feature sets both wipers to -12dB. Power-on reset places the MAX5457 in volumecontrol mode.
USER PRESSES PUSHBUTTON 1 DN OR UP
SWITCH SWITCH CONTACT CONTACT IS BOUNCING IS STABLE
SWITCH CONTACT IS BOUNCING
READY TO ACCEPT ANOTHER KEYPRESS
INPUT ACCEPTED 0 tHPW tIPW tWS
WAIT FOR DEBOUNCE BY FIRST ZERO WAITING FOR CROSSING, tWS STABLE LOW, tIPW
DEBOUNCE BY WAITING FOR STABLE HIGH, tHPW
VH
VL
WIPER MOVES HERE
WIPER MOTION
2dB STEPS
Figure 5a. Wiper Transition Timing Diagram 10 ______________________________________________________________________________________
Stereo Audio Taper Potentiometers with Pushbutton Interface
Shutdown, SHDN
Upon entering shutdown mode, the MAX5456/MAX5457 store the last wiper settings. The wipers move to the L_ end of the resistor string, and the H_ end of the resistor string disconnects from the signal input. Terminating shutdown mode restores the wipers to their previous settings (see Figure 2). Shutdown does not affect the state of MODE_IND. function forces both wipers to maximum attenuation (90dB typ). Deactivating the mute function returns the wipers to their previous settings. Pressing VOLUP also deactivates mute, setting the wipers to their previous positions. MUTE is internally pulled high with a 50k resistor to VLOGIC. When both wipers are in the 31st tap position (-62dB attenuation), further commands to VOLDN place the wipers in the mute position (see Table 1). VOLUP or MUTE pulses return the wipers to position 31.
MAX5456/MAX5457
Mute Function, MUTE
The MAX5456/MAX5457 feature a mute function. Successive pulses on MUTE toggle its setting. Activating the mute
SWITCH SWITCH CONTACT CONTACT IS BOUNCING IS STABLE 1
SWITCH CONTACT IS BOUNCING
READY TO ACCEPT ANOTHER KEYPRESS
INPUT ACCEPTED 0 tHPW tIPW tWS
WAIT FOR DEBOUNCE BY FIRST ZERO WAITING FOR CROSSING OR STABLE LOW, TIMEOUT, tWS tIPW
DEBOUNCE BY WAITING FOR STABLE HIGH, tHPW
VH
VL
WIPER MOVES HERE (tIPW + tWS) 2dB STEPS
Figure 5b. Wiper Transition Timing Diagram ______________________________________________________________________________________ 11
Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Mode Control, MODE
The MAX5457 MODE input toggles between volumeand balance-control modes. Force MODE low to toggle between volume-control and balance-control modes. For example, driving MODE low once while in volumecontrol mode, switches the MAX5457 to balance-control mode. Driving mode low once again, switches the MAX5457 back to volume-control mode. MODE is internally pulled high with a 50k resistor to VLOGIC. The MAX5457 powers up in volume-control mode.
Multiple Button Pushes
The MAX5456/MAX5457 do not respond to simultaneous button pushes. Pushing more than one button at the same time stops the wipers in their present states. Only a single button push configures the device. Additionally, a 40ms blocking period affects all other inputs when releasing any input forced low. The MAX5456/MAX5457 do not respond to any logic input until the blocking period ends. If multiple wiper-control buttons are pressed, all wiper-control connections must be released before the part will respond to further commands.
Mode Indicator, MODE_IND
MODE_IND is the volume-control and balance-control mode indicator with an open-drain output. Connect MODE_IND to an LED through a pullup resistor to VLOGIC. When the LED is on, the MAX5457 is in balancecontrol mode. When the LED is off, the MAX5457 is in volume-control mode. See the Mode Control, MODE section for more detail on switching between modes. Shutdown does not affect the state of MODE_IND.
Applications Information
Stereo Volume/Balance Control
Figure 6 shows a volume/balance application using the MAX5457. The op amp is connected in a follower (noninverting gain) configuration to isolate the potentiometer's wiper impedance from the load and provide drive capability. Connect the W_ of the MAX5457 to the positive input of a noninverting gain amp. The pushbutton potentiometers attenuate the input signals. Use the MODE input to switch between volume-control and balance-control modes.
12
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Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
VDD
VLOGIC
VDD LEFT CHANNEL IN H0
SHDN
VLOGIC
MODE_IND H1 RIGHT CHANNEL IN
L0
L1
MAX5457
VDD / 2 W0 VDD / 2 W1
GND
VSS
MUTE
UP/BAL1
DN/BAL0
MODE
VDD LEFT AUDIO INPUT RIGHT AUDIO INPUT
VDD
INL-
INL+
SHDN
INR+
INR-
MAX4494
VDD SVDD
MAX4494
PGND
MAX9722
OUTL STEREO HEADPHONE
OUTR
Figure 6. Volume/Balance Control ______________________________________________________________________________________ 13
Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Selector Guide
PART MAX5456EEE MAX5456ETE* MAX5457EEE MAX5457ETE* INTERFACE 4-Button 4-Button 3-Button 3-Button PKG. CODE E16-1 T1644-4 E16-1 T1644-4
Chip Information
TRANSISTOR COUNT: 15,395 PROCESS: CMOS
*Future product--contact factory for availability.
Pin Configurations (continued)
TOP VIEW
VOLDN VOLUP VLOGIC 13 12 GND 11 VSS 10 H1 9 5 W0 6 SHDN 7 MUTE 8 W1 L1 VDD 14
VOLDN 1 VOLUP 2 BAL1 3 BAL0 4 H0 5 L0 6 W0 7 SHDN 8
16 16 VDD 15 VLOGIC 14 GND BAL1 BAL0 H0 L0 1 2
15
MAX5456
13 VSS 12 H1 11 L1 10 W1 9 MUTE
MAX5456
3 4
QSOP
DN/BAL0 UP/BAL1 VLOGIC
TQFN
16
15
14
VDD
13
MODE MODE_IND H0 L0
1 2
12 GND 11 VSS
MAX5457
3 4 5 W0 6 SHDN 7 MUTE 8 W1 10 H1 9 L1
TQFN
14
______________________________________________________________________________________
Stereo Audio Taper Potentiometers with Pushbutton Interface
Typical Application Circuit (Single Supply)
VDD H_ RH RL VPEAK VDD / 2 W_ RLOAD = VDD VPEAK VDD / 2
MAX5456/MAX5457
VPEAK VDD / 2
MAX5456/MAX5457
L_
VDD
VDD
Typical Application Circuit (Dual Supplies)
VDD VPEAK 0V RH RL W_ RLOAD = VDD VPEAK 0V
VPEAK 0V
H_
VSS
MAX5456/MAX5457
L_ VSS = -VDD
______________________________________________________________________________________
15
Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Functional Diagrams
VDD
VLOGIC
SHDN
H0
SHUTDOWN 0 1 CLICK/POP SUPPRESSION CIRCUITRY
MAX5456
CLICK/POP SUPPRESSION CIRCUITRY
SHUTDOWN 0 1
H1
2
2
3
3
4 POSITION COUNTER POSITION COUNTER
4
W0 UP/DN 28 TIMING AND CONTROL UP/DN 28
W1
29 DEBOUNCE 30 DEBOUNCE DEBOUNCE DEBOUNCE
T F-F DEBOUNCE VLOGIC
29
30
31 32 MUTE L0
31 32 MUTE L1
VSS
GND
VOLUP
VOLDN
BAL0
BAL1
MUTE
16
______________________________________________________________________________________
Stereo Audio Taper Potentiometers with Pushbutton Interface
Functional Diagrams (continued)
MAX5456/MAX5457
VDD
VLOGIC
SHDN
MODE_IND
H0
SHUTDOWN 0 1 CLICK/POP SUPPRESSION CIRCUITRY
MAX5457
CLICK/POP SUPPRESSION CIRCUITRY
SHUTDOWN 0 1
H1
2
2
3
3
4 POSITION COUNTER POSITION COUNTER
4
W0 UP/DN 28 TIMING AND CONTROL UP/DN 28
W1
29 DEBOUNCE 30 DEBOUNCE
T F-F DEBOUNCE
T F-F DEBOUNCE VLOGIC
29
30
31 32 MUTE L0
31 32 MUTE L1
VSS
GND
DN/BAL0
UP/BAL1
MODE
MUTE
______________________________________________________________________________________
17
Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
QSOP.EPS
PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH
21-0055
E
1
1
18
______________________________________________________________________________________
Stereo Audio Taper Potentiometers with Pushbutton Interface
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
MAX5456/MAX5457
PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
21-0139
D
1
2
______________________________________________________________________________________
19
24L QFN THIN.EPS
Stereo Audio Taper Potentiometers with Pushbutton Interface MAX5456/MAX5457
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
21-0139
D
2
2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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