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19-5140; Rev 1; 4/10
TION KIT EVALUA BLE AVAILA
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
Features
S Dual, 256-Tap Linear Taper Positions S Single +2.6V to +5.5V Supply Operation S Low < 1A Quiescent Supply Current S 10kI, 50kI, 100kI End-to-End Resistance Values S I2C-Compatible Interface S Power-On Sets Wiper to Midscale S -40NC to + 125NC Operating Temperature Range
General Description
The MAX5387 dual, 256-tap, volatile, low-voltage linear taper digital potentiometer offers three end-to-end resistance values of 10kI, 50kI, and 100kI. Operating from a single +2.6V to +5.5V power supply, the device provides a low 35ppm/NC end-to-end temperature coefficient. The device features an I2C interface. The small package size, low supply operating voltage, low supply current, and automotive temperature range of the MAX5387 make the device uniquely suitable for the portable consumer market, battery backup industrial applications, and the automotive market. The MAX5387 is specified over the automotive -40NC to +125NC temperature range and is available in a 14-pin TSSOP package.
MAX5387
Applications
Low-Voltage Battery Applications Portable Electronics Mechanical Potentiometer Replacement Offset and Gain Control Adjustable Voltage References/Linear Regulators Automotive Electronics
PART MAX5387LAUD+ MAX5387MAUD+ MAX5387NAUD+
Ordering Information
PIN-PACKAGE 14 TSSOP 14 TSSOP 14 TSSOP END-TO-END RESISTANCE (kI) 10 50 100
Note: All devices are specified over the -40NC to +125NC operating temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package.
Functional Diagram
VDD HA WA LA
SCL SDA A0 A1 A2 I2C
LATCH POR LATCH
256 DECODER HB
MAX5387
256 DECODER WB LB GND
_______________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
ABSOLUTE MAXIMUM RATINGS
VDD to GND ...........................................................-0.3V to +6V H_, W_, L_ to GND ......................................-0.3V to the lower of (VDD + 0.3V) and +6V All Other Pins to GND .............................................-0.3V to +6V Continuous Current into H_, W_, and L_ MAX5387L ..................................................................... Q5mA MAX5387M .................................................................... Q2mA MAX5387N..................................................................... Q1mA Continuous Power Dissipation (TA = +70NC) 14-Pin TSSOP (derate 10mW/NC above +70NC) ......796.8mW Operating Temperature Range ....................... -40NC to +125NC Junction Temperature ....................................................+150NC Storage Temperature Range............................ -65NC to +150NC Lead Temperature (soldering, 10s) ................................+300NC Soldering Temperature (reflow) ......................................+260NC
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 = +2.6V to +5.5V, VH__ = VDD, VL__= GND, TA = -40NC to +125NC, unless otherwise noted. Typical values are at VDD = +5V, TA = +25NC.) (Note 1) PARAMETER Resolution Integral Nonlinearity Differential Nonlinearity Dual Code Matching Ratiometric Resistor Tempco Full-Scale Error SYMBOL N INL DNL (Note 2) (Note 2) Register A = register B (DVW/VW)/DT; no load MAX5387L Code = FFH MAX5387M MAX5387N MAX5387L Zero-Scale Error DC PERFORMANCE (Variable-Resistor Mode) MAX5387L VDD > +2.6V Integral Nonlinearity R-INL VDD > +4.75V Differential Nonlinearity R-DNL MAX5387M MAX5387N MAX5387L MAX5387M MAX5387N VDD > 2.6V (Note 3) VDD > 2.6V VDD > 4.75V Measured to GND Measured to GND No load Wiper not connected -25 -0.5 250 150 10 50 35 +25 DC PERFORMANCE (Resistor Characteristics) Wiper Resistance (Note 4) Terminal Capacitance Wiper Capacitance End-to-End Resistor Tempco End-to-End Resistor Tolerance RWL CH_, CL_ CW_ TCR DRHL 600 200 I pF pF ppm/NC % 1.0 0.5 0.25 0.4 0.3 0.25 2.5 1.0 0.8 1.5 0.75 0.5 +0.5 LSB LSB Code = 00H MAX5387M MAX5387N -3 -1 -0.5 CONDITIONS MIN 256 -0.5 -0.5 -0.5 +5 -2.5 -0.5 -0.25 +2.5 +0.5 +0.25 +3 +1.0 +0.5 LSB LSB +0.5 +0.5 +0.5 TYP MAX UNITS Tap LSB LSB LSB LSB
DC PERFORMANCE (Voltage-Divider Mode)
2
______________________________________________________________________________________
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.6V to +5.5V, VH__ = VDD, VL__= GND, TA = -40NC to +125NC, unless otherwise noted. Typical values are at VDD = +5V, TA = +25NC.) (Note 1) PARAMETER AC PERFORMANCE Crosstalk -3dB Bandwidth Total Harmonic Distortion Plus Noise Wiper Settling Time (Note 6) POWER SUPPLIES Supply-Voltage Range Standby Current DIGITAL INPUTS Minimum Input High Voltage Maximum Input Low Voltage Input Leakage Current Input Capacitance TIMING CHARACTERISTICS (Notes 7, 8) Maximum SCL Frequency Setup Time for START Condition Hold Time for START Condition SCL High Time SCL Low Time Data Setup Time Data Hold Time SDA, SCL Rise Time SDA, SCL Fall Setup Time for STOP Condition Bus Free Time Between STOP and START Conditions Pulse-Suppressed Spike Width Capacitive Load for Each Bus fSCL tSU:STA tHD:STA tHIGH tLOW tSU:DAT tHD:DAT tR tF tSU:STO tBUF tSP CB Minimum power-up rate = 0.2V/Fs 0.6 1.3 50 400 0.6 0.6 0.6 1.3 100 0 0.3 0.3 400 kHz Fs Fs Fs Fs ns Fs Fs Fs Fs Fs ns pF VIH VIL -1 5 70 30 +1 % x VDD % x VDD FA pF VDD Digital inputs = VDD or GND 2.6 1 5.5 V FA BW (Note 5) Code = 80H, 10pF load, VDD = +2.6V MAX5387L MAX5387M MAX5387N -90 600 150 75 0.015 300 1000 2000 % ns kHz dB SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX5387
THD+N tS
Measured at W; VH_ = 1VRMS at 1kHz MAX5387L MAX5387M MAX5387N
Note 1: All devices are 100% production tested at TA = +25NC. Specifications overtemperature limits are guaranteed by design and characterization. Note 2: DNL and INL are measured with the potentiometer configured as a voltage-divider (Figure 1) with H_ = VDD and L_ = 0V. The wiper terminal is unloaded and measured with an ideal voltmeter. Note 3: R-DNL and R-INL are measured with the potentiometer configured as a variable resistor (Figure 1). DNL and INL are measured with the potentiometer configured as a variable resistor. H_ is unconnected and L_ = GND. For VDD = +5V, the wiper terminal is driven with a source current of 400FA for the 10kI configuration, 80FA for the 50kI configuration, and 40FA for the 100kI configuration. For VDD = +2.6V, the wiper terminal is driven with a source current of 200FA for the 10kI configuration, 40FA for the 50kI configuration, and 20FA for the 100kI configuration. Note 4: The wiper resistance is the worst value measured by injecting the currents given in Note 3 into W_ with L_ = GND. RW = (VW - VH)/IW. _______________________________________________________________________________________ 3
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
Note 5: Drive HA with a 1kHz GND to VDD amplitude tone. LA = LB = GND. No load. WB is at midscale with a 10pF load. Measure WB. Note 6: The wiper settling time is the worst-case 0 to 50% rise time, measured between tap 0 and tap 127. H_ = VDD, L_ = GND, and the wiper terminal is loaded with 10pF capacitance to ground. Note 7: Digital timing is guaranteed by design and characterization, not production tested. Note 8: The SCL clock period includes rise and fall times (tR = tF). All digital input signals are specified with tR = tF = 2ns and timed from a voltage level of (VIL + VIH)/2.
H N.C.
W
W
L
L
Figure 1. Voltage-Divider and Variable Resistor Configurations
Typical Operating Characteristics
(VDD = 5V, TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
MAX5387 toc01
SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE
MAX5387 toc02
0.9 0.8 SUPPLY CURRENT (A) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 VDD = 2.6V VDD = 5V
0.9 0.8 0.7 IDD (A) 0.6 0.5 0.4 0.3 0.2 0.1 0
1000 SUPPLY CURRENT (A) 100 10 1 0.1 0 VDD = 2.6V
VDD = 5V
-40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 DIGITAL INPUT VOLTAGE (V)
2.6
3.1
3.6
4.1 VDD (V)
4.6
5.1
RESISTANCE (W-TO-L) vs. TAP POSITION (10kI)
MAX5387 toc04
RESISTANCE (W-TO-L) vs. TAP POSITION (50kI)
MAX5387 toc05
RESISTANCE (W-TO-L) vs. TAP POSITION (100kI)
100 RESISTANCE (W-TO-L) (kI) 90 80 70 60 50 40 30 20 10 0 0 51 102 153 204 255 TAP POSITION
MAX5387 toc06
11 10 W-TO-L RESISTANCE (k) 9 8 7 6 5 4 3 2 1 0 0 51 102 153 TAP POSITION 204
55 50 W-TO-L RESISTANCE (k) 45 40 35 30 25 20 15 10 5 0
110
255
0
51
102 153 TAP POSITION
204
255
4
______________________________________________________________________________________
MAX5387 toc03
1.0
SUPPLY CURRENT vs. SUPPLY VOLTAGE
1.0
10,000
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
Typical Operating Characteristics (continued)
(VDD = 5V, TA = +25C, unless otherwise noted.)
WIPER RESISTANCE vs. WIPER VOLTAGE (10kI)
MAX5387 toc07
MAX5387
END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE
10kI
MAX5387 toc08
VARIABLE-RESISTOR DNL vs. TAP POSITION (10kI)
0.08 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.10
IWIPER = 400A
190 WIPER RESISTANCE () 170 150 130 110 90 70 VDD = 5V
VDD = 2.6V
END-TO-END RESISTANCE % CHANGE
0 -0.1
50kI
-0.2 -0.3 -0.4 -0.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (NC)
100kI
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V)
DNL (LSB)
0
51
102
153
204
255
TAP POSITION
VARIABLE-RESISTOR DNL vs. TAP POSITION (50kI)
MAX5387 toc10
VARIABLE-RESISTOR DNL vs. TAP POSITION (100kI)
MAX5387 toc11
VARIABLE-RESISTOR INL vs. TAP POSITION (10kI)
0.8 0.6 0.4 INL (LSB) 0.2 0 -0.2 -0.4 -0.6 -0.8 -1.0
0.08 0.06 0.04 DNL (LSB) 0 -0.02 -0.04 -0.06 -0.08 -0.10 0 0.02
IWIPER = 80A
0.08 0.06 0.04 DNL (LSB) 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.10
IWIPER = 400A
IWIPER = 400A
51
102
153
204
255
0
51
102
153
204
255
0
51
102
153
204
255
TAP POSITION
TAP POSITION
TAP POSITION
VARIABLE-RESISTOR INL vs. TAP POSITION (50kI)
MAX5387 toc13
VARIABLE-RESISTOR INL vs. TAP POSITION (100kI)
MAX5387 toc14
VOLTAGE-DIVIDER DNL vs. TAP POSITION (10kI)
0.08 0.06 0.04 DNL (LSB) 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.10
MAX5386 toc15
0.5 0.4 0.3 0.2 INL (LSB) 0 -0.1 -0.2 -0.3 -0.4 -0.5 0 0.1
IWIPER = 80A
0.5 0.4 0.3 0.2 INL (LSB) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5
IWIPER = 400A
0.10
51
102
153
204
255
0
51
102
153
204
255
0
51
102
153
204
255
TAP POSITION
TAP POSITION
TAP POSITION
_______________________________________________________________________________________
5
MAX5387 toc12
0.10
0.10
1.0
MAX5387 toc09
210
0.1
0.10
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
Typical Operating Characteristics (continued)
(VDD = 5V, TA = +25C, unless otherwise noted.)
VOLTAGE-DIVIDER DNL vs. TAP POSITION (50kI)
MAX5387 toc16
VOLTAGE-DIVIDER DNL vs. TAP POSITION (100kI)
MAX5387 toc17
VOLTAGE-DIVIDER INL vs. TAP POSITION (10kI)
0.4 0.3 0.2 INL (LSB) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5
MAX5387 toc18
0.10 0.08 0.06 0.04 DNL (LSB) 0 -0.02 -0.04 -0.06 -0.08 -0.10 0 51 102 153 204 0.02
0.10 0.08 0.06 0.04 DNL (LSB) 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.10
0.5
255
0
51
102
153
204
255
0
51
102
153
204
255
TAP POSITION
TAP POSITION
TAP POSITION
VOLTAGE-DIVIDER INL vs. TAP POSITION (50kI)
MAX5386 toc19
VOLTAGE-DIVIDER INL vs. TAP POSITION (100kI)
0.4 0.3 0.2 INL (LSB) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5
MAX5387 toc20
TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128) (10kI)
0.5 0.4 0.3 0.2 INL (LSB) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 0 51 102 153 204
0.5
MAX5387 toc21
VW-L 20mV/div
SCL 5V/div
255
0
51
102
153
204
255
400ns/div
TAP POSITION
TAP POSITION
TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128) (50kI)
MAX5387 toc22
TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128) (100kI)
VW-L 20mV/div
MAX5387 toc23
VW-L 20mV/div
SCL 5V/div
SCL 5V/div
1s/div
1s/div
6
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Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
Typical Operating Characteristics (continued)
(VDD = 5V, TA = +25C, unless otherwise noted.)
MAX5387
MAX5387 POWER-ON WIPER TRANSIENT (CODE 0 TO 128)
MAX5387 toc24
MIDSCALE FREQUENCY RESPONSE
VIN = 1VP-P CW = 10pF
MAX5387 toc25
10
0 GAIN (dB)
OUTPUT W 2V/div
-10
MAX5387L MAX5387M
VDD 2V/div
-20
MAX5387N
-30 0.01 0.1 1 10 100 1,000 10,000 FREQUENCY (kHz)
2s/div
CROSSTALK vs. FREQUENCY
MAX5387 toc26
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
0.12 0.10 THD+N (%) 0.08 0.06 0.04 0.02 0
MAX5387 toc27
0 -20 CROSSTALK (dB) -40 -60 -80 -100 -120 -140 0.01 0.1 1 10 100
0.14
MAX5387M
MAX5387L
MAX5387N
MAX5387N MAX5387M
MAX5387L
1000
0.01
0.10
1 FREQUENCY (kHz)
10
100
FREQUENCY (kHz)
_______________________________________________________________________________________
7
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
Pin Configuration
TOP VIEW
HA 1 WA 2 LA 3 HB 4 WB 5 LB 6 I.C. 7
+
14 VDD 13 SCL
MAX5387
12 SDA 11 A0 10 A1 9 A2 8 GND
TSSOP
Pin Description
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 NAME HA WA LA HB WB LB I.C. GND A2 A1 A0 SDA SCL VDD FUNCTION Resistor A High Terminal. The voltage at HA can be higher or lower than the voltage at LA. Current can flow into or out of HA. Resistor A Wiper Terminal Resistor A Low Terminal. The voltage at LA can be higher or lower than the voltage at HA. Current can flow into or out of LA. Resistor B High Terminal. The voltage at HB can be higher or lower than the voltage at LB. Current can flow into or out of HB. Resistor B Wiper Terminal Resistor B Low Terminal. The voltage at LB can be higher or lower than the voltage at HB. Current can flow into or out of LB. Internally Connected. Connect to GND. Ground Address Input 2. Connect to VDD or GND. Address Input 1. Connect to VDD or GND. Address Input 0. Connect to VDD or GND. I2C-Compatible Serial-Data Input/Output. A pullup resistor is required. I2C-Compatible Serial-Clock Input. A pullup resistor is required. Power-Supply Input. Bypass VDD to GND with a 0.1FF capacitor close to the device.
8
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Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
Detailed Description
The MAX5387 dual, 256-tap, volatile, low-voltage linear taper digital potentiometer offers three end-to-end resistance values of 10kI, 50kI, and 100kI. The potentiometer consists of 255 fixed resistors in series between terminals H_ and L_. The potentiometer wiper, W_, is programmable to access any one of the 256 tap points on the resistor string. The potentiometers are programmable independently of each other. The MAX5387 features an I2C interface. The I2C interface contains a shift register that decodes the command and address bytes, routing the data to the appropriate control registers. Data written to a control register immediately updates the wiper position. Wipers A and B power up in midposition, D[7:0] = 80H. The MAX5387 operates as a slave device that receives data through an I2C-/SMBusK-compatible 2-wire serial interface. The interface uses a serial-data access (SDA) line and a serial-clock line (SCL) to achieve bidirectional communication between master(s) and slave(s). A master, typically a microcontroller, initiates all data transfers to the MAX5387, and generates the SCL clock that synchronizes the data transfer (Figure 2). The MAX5387 SDA line operates as both an input and an open-drain output. The SDA line requires a pullup resistor, typically 4.7kI. The MAX5387 SCL line operates only as an input. The SCL line requires a pullup resistor (typically 4.7kI) if there are multiple masters on the 2-wire interface, or if the master in a single-master system provides an open-drain SCL output. Each transmission consists of a START (S) condition (Figure 3) sent by a master, followed by the MAX5387 7-bit slave address plus the NOP/W bit (Figure 6), 1 command byte and 1 data byte, and finally a STOP (P) condition (Figure 3). START and STOP Conditions SCL and SDA remain high when the interface is inactive. A master controller signals the beginning of a transmission with a START condition by transitioning SDA from high to low while SCL is high. The master controller issues a STOP condition by transitioning the SDA from low to high while SCL is high, after finishing communicating with the slave. The bus is then free for another transmission.
MAX5387
I2C Digital Interface
Serial Addressing
tHD:STA SDA tSU:DAT tLOW SCL tHD:STA tR START CONDITION (S) tHIGH tF REPEATED START CONDITION (Sr) ACKNOWLEDGE (A) tHD-DAT tSU:DTA
tSU:STD
tBUF
STOP CONDITION START CONDITION (P) (S)
Figure 2. I2C Serial Interface Timing Diagram
SMBus is a trademark of Intel Corp. _______________________________________________________________________________________ 9
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
Bit Transfer One data bit is transferred during each clock pulse. The data on the SDA line must remain stable while SCL is high. See Figure 4. Acknowledge The acknowledge bit is a clocked 9th bit that the recipient uses to handshake receipt of each byte of data. See Figure 5. Each byte transferred requires a total of nine bits. The master controller generates the 9th clock pulse, and the recipient pulls down SDA during the acknowledge clock pulse, so the SDA line remains stable low during the high period of the clock pulse. Slave Address The MAX5387 includes a 7-bit slave address (Figure 6). The 8th bit following the 7th bit of the slave address is the NOP/W bit. Set the NOP/W bit low for a write command and high for a no-operation command. The device does not support readback. The device provides three address inputs (A0, A1, and A2), allowing up to eight devices to share a common bus (Table 1). The first 4 bits (MSBs) of the factory-set slave addresses are always 0101. A2, A1, and A0 set the next 3 bits of the slave address. Connect each address input to VDD or GND. Each device must have a unique address to share a common bus.
SDA
SCL S START CONDITION P
STOP CONDITION
Figure 3. START and STOP Conditions
SDA
CHANGE OF DATA ALLOWED
SCL
DATA STABLE, DATA VALID
Figure 4. Bit Transfer
CLOCK PULSE FOR ACKNOWLEDGMENT START CONDITION SCL 1 2 8 NOT ACKNOWLEDGE SDA 9
ACKNOWLEDGE
Figure 5. Acknowledge 10 _____________________________________________________________________________________
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
SDA 0 1 0 1 A2 A1 A0 NOP/W ACK
START SCL
MSB
LSB
Figure 6. Slave Address
ACKNOWLEDGE HOW CONTROL BYTE AND DATA BYTE MAP INTO DEVICE REGISTERS ACKNOWLEDGE S 0 A A A P R7 R6 R5 R4 R3 R2 R1 R0 D7 D6 D5 D4 D3 D2 D1 D0
SLAVE ADDRESS NOP/W
COMMAND BYTE
1 DATA BYTE
Figure 7. Command and Single Data Byte Received
Message Format for Writing Write to the devices by transmitting the device's slave address with NOP/W (eighth bit) set to zero, followed by at least 2 bytes of information. The first byte of information is the command byte. The second byte is the data byte. The data byte goes into the internal register of the device as selected by the command byte (Figure 7 and Table 2). Command Byte Use the command byte to select the destination of the wiper data. See Table 2. Command Descriptions REG A: The data byte writes to register A and the wiper of potentiometer A moves to the appropriate position. D[7:0] indicates the position of the wiper. D[7:0] = 00h
moves the wiper to the position closest to LA. D[7:0] = FFh moves the wiper to the position closest to HA. D[7:0] is 80h following power-on.
Table 1. Slave Addresses
ADDRESS INPUTS A2 GND GND GND GND VDD VDD VDD VDD A1 GND GND VDD VDD GND GND VDD VDD A0 GND VDD GND VDD GND VDD GND VDD SLAVE ADDRESS 0101000 0101001 0101010 0101011 0101100 0101101 0101110 0101111
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11
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
Table 2. I2C Command Byte Summary
ADDRESS BYTE 1 START (S) SCL CYCLE NO. 2 3 4 5 6 7 8 9 ACK (A) 10 11 12 COMMAND BYTE 13 14 15 16 17 18 ACK (A) 19 20 21 DATA BYTE 22 23 24 25 26 27 ACK (A) STOP (P)
A6
A5
A4
A3
A2
A1
A0
W
R7
R6
R5
R4
R3
R2
R1
R0
D7
D6
D5
D4
D3
D2
D1
D0
REG A REG B REGS A AND B
0 0 0
1 1 1
0 0 0
1 1 1
A2 A2 A2
A1 A1 A1
A0 A0 A0
0 0 0
0 0 0
0 0 0
0 0 0
1 1 1
0 0 0
0 0 0
0 1 1
1 0 1
D7 D7 D7
D6 D6 D6
D5 D5 D5
D4 D4 D4
D3 D3 D3
D2 D2 D2
D1 D1 D1
D0 D0 D0
REG B: The data byte writes to register B and the wiper of potentiometer B moves to the appropriate position. D[7:0] indicates the position of the wiper. D[7:0] = 00h moves the wiper to the position closest to LB. D[7:0] = FFh moves the wiper to the position closest to HB. D[7:0] is 80h following power-on. REGS A and B: The data byte writes to registers A and B and the wipers of potentiometers A and B move to the appropriate position. D[7:0] indicates the position of the wiper. D[7:0] = 00h moves the wipers to the position closest to L_. D[7:0] = FFh moves the wipers to the position closest to H_. D[7:0] is 80h following power-on.
Figure 10 shows an adjustable dual linear regulator using a dual potentiometer as two variable resistors.
Adjustable Dual Regulator
Figure 11 shows an adjustable voltage reference circuit using a potentiometer as a voltage-divider.
H W VIN VOUT L
Adjustable Voltage Reference
Applications Information
Figure 8 shows a potentiometer adjusting the gain of a noninverting amplifier. Figure 9 shows a potentiometer adjusting the gain of an inverting amplifier.
Variable Gain Amplifier
Figure 9. Variable Gain Inverting Amplifier
VOUT1 VOUT2
OUT1
VIN VOUT
OUT2
MAX8866
V+
W L H
H
H
IN
W SET1 SET2 L L
W
Figure 8. Variable Gain Noninverting Amplifier
Figure 10. Adjustable Dual Linear Regulator
12
_____________________________________________________________________________________
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
Figure 12 shows a variable gain current to voltage converter using a potentiometer as a variable resistor. Figure 13 shows a positive LCD bias control circuit using a potentiometer as a voltage-divider. Figure 14 shows a positive LCD bias control circuit using a potentiometer as a variable resistor.
Variable Gain Current to Voltage Converter
Figure 15 shows a programmable filter using a dual potentiometer. Figure 16 shows an offset-voltage adjustment circuit using a dual potentiometer.
Programmable Filter
MAX5387
LCD Bias Control
Offset-Voltage Adjustment Circuit
3.0V IN OUT H W VREF
+5V H W
VOUT
MAX6037
L GND L
Figure 11. Adjustable Voltage Reference
Figure 13. Positive LCD Bias Control Using a Voltage-Divider
+5V R3 H W
IS
R1 L
R2
H W
VOUT
VOUT
L
VOUT = IS x ((R3 x (1 + R2/R1)) + R2)
Figure 12. Variable Gain I-to-V Converter
Figure 14. Positive LCD Bias Control Using a Variable Resistor
______________________________________________________________________________________
13
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387
+5V WB
VIN
WA LB HA
VOUT VOUT
LA
HB R3
R1 HA R2 LA HB
WA
WB LB
Figure 15. Programmable Filter
Figure 16. Offset-Voltage Adjustment Circuit
Process Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE TYPE 14 TSSOP PACKAGE CODE U14+1 DOCUMENT NO. 21-0066
14
_____________________________________________________________________________________
Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
Revision History
REVISION NUMBER 0 1 REVISION DATE 1/10 4/10 Initial release Added Soldering Temperature in Absolute Maximum Ratings; corrected code in Conditions of -3dB Bandwidth specification in Electrical Characteristics DESCRIPTION PAGES CHANGED -- 2
MAX5387
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
(c)
15
2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.

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