19-5140; Rev 1; 4/10 TION KIT EVALUA BLE AVAILA Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer Features 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. S Dual, 256-Tap Linear Taper Positions 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. S Power-On Sets Wiper to Midscale S Single +2.6V to +5.5V Supply Operation S Low < 1µA Quiescent Supply Current S 10kI, 50kI, 100kI End-to-End Resistance Values S I2C-Compatible Interface S -40NC to + 125NC Operating Temperature Range The MAX5387 is specified over the automotive -40NC to +125NC temperature range and is available in a 14-pin TSSOP package. Ordering Information Applications Low-Voltage Battery Applications PART Portable Electronics PIN-PACKAGE END-TO-END RESISTANCE (kI) Mechanical Potentiometer Replacement MAX5387LAUD+ 14 TSSOP Offset and Gain Control MAX5387MAUD+ 14 TSSOP 50 MAX5387NAUD+ 14 TSSOP 100 Adjustable Voltage References/Linear Regulators 10 Note: All devices are specified over the -40NC to +125NC operating temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. Automotive Electronics Functional Diagram VDD SCL HA LATCH WA 256 DECODER SDA A0 HB I2C POR MAX5387 A1 A2 LA LATCH 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. MAX5387 General Description MAX5387 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer ABSOLUTE MAXIMUM RATINGS 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 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 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 SYMBOL CONDITIONS N MIN TYP MAX 256 UNITS Tap DC PERFORMANCE (Voltage-Divider Mode) Integral Nonlinearity INL (Note 2) -0.5 +0.5 LSB Differential Nonlinearity DNL (Note 2) -0.5 +0.5 LSB Dual Code Matching Register A = register B -0.5 +0.5 LSB Ratiometric Resistor Tempco (DVW/VW)/DT; no load Full-Scale Error Code = FFH Zero-Scale Error Code = 00H +5 MAX5387L -3 -2.5 MAX5387M -1 -0.5 MAX5387N -0.5 -0.25 LSB LSB MAX5387L +2.5 +3 MAX5387M +0.5 +1.0 MAX5387N +0.25 +0.5 LSB DC PERFORMANCE (Variable-Resistor Mode) VDD > +2.6V Integral Nonlinearity R-INL VDD > +4.75V MAX5387L ±1.0 ±2.5 MAX5387M ±0.5 ±1.0 MAX5387N ±0.25 ±0.8 MAX5387L ±0.4 ±1.5 MAX5387M ±0.3 ±0.75 ±0.25 ±0.5 MAX5387N Differential Nonlinearity R-DNL VDD > 2.6V (Note 3) -0.5 +0.5 LSB LSB DC PERFORMANCE (Resistor Characteristics) Wiper Resistance (Note 4) RWL VDD > 2.6V 250 600 VDD > 4.75V 150 200 I CH_, CL_ Measured to GND 10 pF CW_ Measured to GND 50 pF End-to-End Resistor Tempco TCR No load End-to-End Resistor Tolerance DRHL Wiper not connected Terminal Capacitance Wiper Capacitance 35 -25 2 _______________________________________________________________________________________ ppm/NC +25 % Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer (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 SYMBOL CONDITIONS MIN TYP MAX UNITS AC PERFORMANCE Crosstalk (Note 5) -3dB Bandwidth BW Total Harmonic Distortion Plus Noise Wiper Settling Time (Note 6) THD+N tS Code = 80H, 10pF load, VDD = +2.6V -90 MAX5387L 600 MAX5387M 150 MAX5387N 75 dB kHz Measured at W; VH_ = 1VRMS at 1kHz 0.015 % MAX5387L MAX5387M MAX5387N 300 1000 2000 ns POWER SUPPLIES Supply-Voltage Range 2.6 VDD Digital inputs = VDD or GND Standby Current 5.5 1 V FA DIGITAL INPUTS Minimum Input High Voltage VIH Maximum Input Low Voltage VIL 70 Input Leakage Current % x VDD -1 Input Capacitance 30 % x VDD +1 FA 5 pF TIMING CHARACTERISTICS (Notes 7, 8) Maximum SCL Frequency 400 fSCL kHz Setup Time for START Condition tSU:STA 0.6 Fs Hold Time for START Condition tHD:STA 0.6 Fs SCL High Time tHIGH 0.6 Fs SCL Low Time tLOW 1.3 Fs Data Setup Time tSU:DAT 100 ns Data Hold Time tHD:DAT 0 Fs SDA, SCL Rise Time tR 0.3 Fs SDA, SCL Fall tF 0.3 Fs Setup Time for STOP Condition Bus Free Time Between STOP and START Conditions tSU:STO tBUF Minimum power-up rate = 0.2V/Fs 0.6 Fs 1.3 Fs Pulse-Suppressed Spike Width tSP 50 ns Capacitive Load for Each Bus CB 400 pF 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 MAX5387 ELECTRICAL CHARACTERISTICS (continued) 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 = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE VDD = 5V 0.7 0.6 0.5 0.4 VDD = 2.6V 0.3 1000 SUPPLY CURRENT (µA) 0.2 VDD = 5V 1.0 0.9 0.8 0.7 100 VDD = 2.6V 10 0.6 0.5 0.4 0.3 0.2 1 0.1 0.1 0 0 0.1 -40 -25 -10 5 20 35 50 65 80 95 110 125 0 2.6 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 3.6 4.1 4.6 5.1 DIGITAL INPUT VOLTAGE (V) VDD (V) RESISTANCE (W-TO-L) vs. TAP POSITION (10kI) RESISTANCE (W-TO-L) vs. TAP POSITION (50kI) RESISTANCE (W-TO-L) vs. TAP POSITION (100kI) W-TO-L RESISTANCE (kΩ) 9 50 8 7 6 5 4 3 110 45 100 RESISTANCE (W-TO-L) (kI) 10 MAX5387 toc05 55 MAX5387 toc04 11 40 35 30 25 20 15 90 80 70 60 50 40 30 2 10 20 1 5 10 0 0 0 3.1 TEMPERATURE (°C) 51 102 153 TAP POSITION 204 255 0 51 102 153 TAP POSITION 204 255 MAX5387 toc06 SUPPLY CURRENT (µA) 0.8 10,000 MAX5387 toc03 0.9 IDD (µA) MAX5387 toc01 1.0 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX5387 toc02 SUPPLY CURRENT vs. TEMPERATURE W-TO-L RESISTANCE (kΩ) MAX5387 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer 0 0 51 102 153 TAP POSITION 4 _______________________________________________________________________________________ 204 255 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE 110 90 50kI -0.2 100kI -0.3 -0.06 -0.4 -0.08 -0.10 0 1.0 0.06 0.6 0.2 INL (LSB) 0.4 0 -0.02 0 -0.04 -0.4 -0.06 -0.06 -0.6 -0.08 -0.08 -0.8 -0.10 204 -1.0 0 51 102 153 204 255 0 102 153 204 TAP POSITION TAP POSITION VARIABLE-RESISTOR INL vs. TAP POSITION (50kI) VARIABLE-RESISTOR INL vs. TAP POSITION (100kI) VOLTAGE-DIVIDER DNL vs. TAP POSITION (10kI) 0.5 IWIPER = 400µA 0.4 0.10 MAX5387 toc14 0.3 0.3 0.08 0.06 0.04 0.1 0.1 0.02 0 -0.1 DNL (LSB) 0.2 INL (LSB) 0.2 0 -0.1 0 -0.2 -0.04 -0.3 -0.3 -0.06 -0.4 -0.4 -0.08 -0.5 -0.5 51 102 153 TAP POSITION 204 255 255 -0.02 -0.2 0 51 TAP POSITION IWIPER = 80µA 0.4 255 MAX5387 toc13 0.5 153 255 -0.2 -0.04 102 IWIPER = 400µA 0.8 0.02 51 204 VARIABLE-RESISTOR INL vs. TAP POSITION (10kI) 0.02 0 153 VARIABLE-RESISTOR DNL vs. TAP POSITION (100kI) 0.04 -0.02 102 TAP POSITION 0.04 0 51 TEMPERATURE (NC) IWIPER = 400µA 0.08 -0.10 INL (LSB) 0 -0.02 -0.04 0.10 DNL (LSB) DNL (LSB) 0.06 0.02 -40 -25 -10 5 20 35 50 65 80 95 110 125 MAX5387 toc10 IWIPER = 80µA 0.08 MAX5387 toc09 0.04 -0.1 VARIABLE-RESISTOR DNL vs. TAP POSITION (50kI) 0.10 0.06 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V) IWIPER = 400µA 0.08 MAX5386 toc15 70 0 MAX5387 toc12 VDD = 5V 130 0.10 DNL (LSB) 150 10kI MAX5387 toc11 170 0.1 END-TO-END RESISTANCE % CHANGE VDD = 2.6V 190 WIPER RESISTANCE (Ω) MAX5387 toc07 210 VARIABLE-RESISTOR DNL vs. TAP POSITION (10kI) MAX5387 toc08 WIPER RESISTANCE vs. WIPER VOLTAGE (10kI) -0.10 0 51 102 153 TAP POSITION 204 255 0 51 102 153 204 255 TAP POSITION _______________________________________________________________________________________ 5 MAX5387 Typical Operating Characteristics (continued) (VDD = 5V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VDD = 5V, TA = +25°C, unless otherwise noted.) 0.06 VOLTAGE-DIVIDER INL vs. TAP POSITION (10kI) 0.5 MAX5387 toc17 0.08 0.08 0.06 0.4 0.3 0.04 0.2 0.02 0.02 0.1 0 -0.02 INL (LSB) 0.04 DNL (LSB) 0 -0.02 0 -0.1 -0.04 -0.04 -0.2 -0.06 -0.06 -0.3 -0.08 -0.08 -0.4 -0.10 -0.10 0 51 102 153 204 255 -0.5 0 51 102 153 204 255 0 51 102 153 255 TAP POSITION TAP POSITION VOLTAGE-DIVIDER INL vs. TAP POSITION (50kI) VOLTAGE-DIVIDER INL vs. TAP POSITION (100kI) TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128) (10kI) 0.4 0.3 0.4 0.3 0.2 0.1 0.1 INL (LSB) 0.2 0 -0.1 VW-L 20mV/div 0 -0.1 -0.2 -0.2 -0.3 -0.3 -0.4 -0.4 -0.5 MAX5387 toc21 0.5 MAX5386 toc19 0.5 SCL 5V/div -0.5 0 204 TAP POSITION MAX5387 toc20 DNL (LSB) 0.10 MAX5387 toc16 0.10 VOLTAGE-DIVIDER DNL vs. TAP POSITION (100kI) MAX5387 toc18 VOLTAGE-DIVIDER DNL vs. TAP POSITION (50kI) INL (LSB) MAX5387 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer 51 102 153 204 255 0 51 TAP POSITION 102 153 204 255 400ns/div TAP POSITION TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128) (50kI) TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128) (100kI) MAX5387 toc22 1µs/div MAX5387 toc23 VW-L 20mV/div VW-L 20mV/div SCL 5V/div SCL 5V/div 1µs/div 6 _______________________________________________________________________________________ Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387 POWER-ON WIPER TRANSIENT (CODE 0 TO 128) 10 MAX5387 toc25 MIDSCALE FREQUENCY RESPONSE MAX5387 toc24 VIN = 1VP-P CW = 10pF GAIN (dB) 0 OUTPUT W 2V/div MAX5387L -10 MAX5387M -20 VDD 2V/div MAX5387N -30 2µs/div 0.01 0.1 1 10 100 1,000 10,000 FREQUENCY (kHz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY CROSSTALK vs. FREQUENCY 0.12 MAX5387L -60 -80 -100 MAX5387N MAX5387M -120 MAX5387M 0.10 THD+N (%) -40 MAX5387 toc27 -20 CROSSTALK (dB) 0.14 MAX5387 toc26 0 -140 0.08 MAX5387N 0.06 0.04 MAX5387L 0.02 0 0.01 0.1 1 10 FREQUENCY (kHz) 100 1000 0.01 0.10 1 10 100 FREQUENCY (kHz) _______________________________________________________________________________________ 7 MAX5387 Typical Operating Characteristics (continued) (VDD = 5V, TA = +25°C, unless otherwise noted.) Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer MAX5387 Pin Configuration TOP VIEW HA 1 + 14 VDD 13 SCL WA 2 LA 3 MAX5387 12 SDA HB 4 11 A0 WB 5 10 A1 LB 6 9 A2 I.C. 7 8 GND TSSOP Pin Description PIN NAME FUNCTION 1 HA 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. 2 WA Resistor A Wiper Terminal 3 LA 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. 4 HB 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. 5 WB Resistor B Wiper Terminal 6 LB 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. 7 I.C. Internally Connected. Connect to GND. 8 GND 9 A2 Address Input 2. Connect to VDD or GND. 10 A1 Address Input 1. Connect to VDD or GND. 11 A0 12 SDA Address Input 0. Connect to VDD or GND. I2C-Compatible Serial-Data Input/Output. A pullup resistor is required. 13 SCL I2C-Compatible Serial-Clock Input. A pullup resistor is required. 14 VDD Power-Supply Input. Bypass VDD to GND with a 0.1FF capacitor close to the device. Ground 8 _______________________________________________________________________________________ Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer 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. I2C Digital 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. Serial Addressing 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. tHD:STA SDA tSU:STD tSU:DTA tSU:DAT tBUF tHD-DAT tLOW SCL tHIGH tHD:STA tR tF REPEATED START CONDITION (Sr) START CONDITION (S) ACKNOWLEDGE (A) STOP CONDITION START CONDITION (P) (S) Figure 2. I2C Serial Interface Timing Diagram SMBus is a trademark of Intel Corp. _______________________________________________________________________________________ 9 MAX5387 Detailed Description MAX5387 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer 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 P S START CONDITION STOP CONDITION Figure 3. START and STOP Conditions SDA CHANGE OF DATA ALLOWED DATA STABLE, DATA VALID SCL Figure 4. Bit Transfer CLOCK PULSE FOR ACKNOWLEDGMENT START CONDITION SCL 1 2 8 9 NOT ACKNOWLEDGE SDA ACKNOWLEDGE Figure 5. Acknowledge 10 ������������������������������������������������������������������������������������� Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer START 0 1 0 1 A2 A1 A0 MSB NOP/W MAX5387 SDA ACK LSB SCL Figure 6. Slave Address ACKNOWLEDGE HOW CONTROL BYTE AND DATA BYTE MAP INTO DEVICE REGISTERS R7 R6 R5 R4 R3 R2 R1 R0 D7 D6 D5 D4 D3 D2 D1 D0 ACKNOWLEDGE S 0 A SLAVE ADDRESS A A COMMAND BYTE P 1 DATA BYTE NOP/W 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 SLAVE ADDRESS A2 A1 A0 GND GND GND 0101000 GND GND VDD 0101001 GND VDD GND 0101010 GND VDD VDD 0101011 VDD GND GND 0101100 VDD GND VDD 0101101 VDD VDD GND 0101110 VDD VDD VDD 0101111 ______________________________________________________________________________________ 11 Table 2. I2C Command Byte Summary SCL CYCLE NO. COMMAND BYTE 1 2 3 4 5 6 7 8 A6 A5 A4 A3 A2 A1 A0 W 9 ACK (A) DATA BYTE 10 11 12 13 14 15 16 17 R7 R6 R5 R4 R3 R2 R1 R0 18 ACK (A) 19 20 21 22 23 24 25 26 D7 D6 D5 D4 D3 D2 D1 D0 REG A 0 1 0 1 A2 A1 A0 0 0 0 0 1 0 0 0 1 D7 D6 D5 D4 D3 D2 D1 D0 REG B 0 1 0 1 A2 A1 A0 0 0 0 0 1 0 0 1 0 D7 D6 D5 D4 D3 D2 D1 D0 0 1 0 1 A2 A1 A0 0 0 0 0 1 0 0 1 1 D7 D6 D5 D4 D3 D2 D1 D0 REGS A AND B 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. 27 ACK (A) Adjustable Dual Regulator Figure 10 shows an adjustable dual linear regulator using a dual potentiometer as two variable resistors. Adjustable Voltage Reference Figure 11 shows an adjustable voltage reference circuit using a potentiometer as a voltage-divider. H L W VIN VOUT Applications Information Variable Gain Amplifier Figure 8 shows a potentiometer adjusting the gain of a noninverting amplifier. Figure 9 shows a potentiometer adjusting the gain of an inverting amplifier. Figure 9. Variable Gain Inverting Amplifier VOUT1 OUT1 VIN VOUT2 OUT2 VOUT H MAX8866 V+ W L STOP (P) ADDRESS BYTE START (S) MAX5387 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer IN H W H SET1 W L L SET2 Figure 8. Variable Gain Noninverting Amplifier Figure 10. Adjustable Dual Linear Regulator 12 ������������������������������������������������������������������������������������� Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer LCD Bias Control Figure 13 shows a positive LCD bias control circuit using a potentiometer as a voltage-divider. Programmable Filter Figure 15 shows a programmable filter using a dual potentiometer. Offset-Voltage Adjustment Circuit Figure 16 shows an offset-voltage adjustment circuit using a dual potentiometer. Figure 14 shows a positive LCD bias control circuit using a potentiometer as a variable resistor. 3.0V +5V IN VREF OUT MAX6037 H H W W VOUT L L GND Figure 11. Adjustable Voltage Reference Figure 13. Positive LCD Bias Control Using a Voltage-Divider +5V R3 H W R1 R2 H W IS L 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 MAX5387 Variable Gain Current to Voltage Converter Figure 12 shows a variable gain current to voltage converter using a potentiometer as a variable resistor. MAX5387 Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer +5V WA WB VIN LA HA LB HB VOUT R3 VOUT R1 HA HB R2 WA LA 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 PACKAGE CODE Document No. 14 TSSOP U14+1 21-0066 14 ������������������������������������������������������������������������������������� Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer REVISION NUMBER REVISION DATE 0 1/10 Initial release — 1 4/10 Added Soldering Temperature in Absolute Maximum Ratings; corrected code in Conditions of -3dB Bandwidth specification in Electrical Characteristics 2 DESCRIPTION PAGES CHANGED 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 © 2010 Maxim Integrated Products 15 Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX5387 Revision History