EVALUATION KIT AVAILABLE MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers General Description Benefits and Features The MAX5487/MAX5488/MAX5489 dual, linear-taper, digital potentiometers function as mechanical potentiometers with a simple 3-wire SPITM-compatible digital interface that programs the wipers to any one of 256 tap positions. These digital potentiometers feature a nonvolatile memory (EEPROM) to return the wipers to their previously stored positions upon power-up. Wiper Position Stored in Nonvolatile Memory (EEPROM) and Recalled Upon Power-Up or Recalled by an Interface Command 3mm x 3mm x 0.8mm, 16-Pin TQFN or 14-Pin TSSOP Packages 1 LSB INL, 0.5 LSB DNL (Voltage-Divider Mode) 256 Tap Positions The MAX5487 has an end-to-end resistance of 10k, while the MAX5488 and MAX5489 have resistances of 50k and 100k, respectively. These devices have a low 35ppm/C end-to-end temperature coefficient, and operate from a single +2.7V to +5.25V supply. 35ppm/C End-to-End Resistance Temperature Coefficient 5ppm/C Ratiometric Temperature Coefficient 10k, 50k, and 100k End-to-End Resistance Values The MAX5487/MAX5488/MAX5489 are available in 16-pin 3mm x 3mm x 0.8mm TQFN or 14-pin TSSOP packages. Each device is guaranteed over the extended -40C to +85C temperature range. SPI-Compatible Serial Interface Reliability * 200,000 Wiper Store Cycles * 50-Year Wiper Data Retention Applications LCD Screen Adjustment Audio Volume Control Mechanical Potentiometer Replacement Low-Drift Programmable Filters Low-Drift Programmable-Gain Amplifiers +2.7V to +5.25V Single-Supply Operation SPI is a trademark of Motorola, Inc. Functional Diagram HA VDD SCLK DIN CS 8 8-BIT LATCH GND SPI INTERFACE 16-BIT NV RAM 8-BIT LATCH DECODER WA LA POR HB 8 256 DECODER MAX5487 MAX5488 MAX5489 19-3478; Rev 4; 4/10 256 WB LB MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Absolute Maximum Ratings VDD to GND..........................................................-0.3V to +6.0V All Other Pins to GND..............-0.3V to the lower of (VDD + 0.3V) and +6.0V Maximum Continuous Current into H_, W_, and L_ MAX5487......................................................................5.0mA MAX5488......................................................................1.3mA MAX5489......................................................................0.6mA Continuous Power Dissipation (TA = +70C) 16-Pin TQFN (derate 17.5mW/C above +70C).......1398mW 14-Pin TSSOP (derate 9.1mW/C above +70C).........727mW Operating Temperature Range............................ -40C to +85C Junction Temperature.......................................................+150C Storage Temperature Range............................. -60C to +150C Lead Temperature (soldering, 10s).................................. +300C Soldering Temperature (reflow)........................................+260C 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. DC Electrical Characteristics (VDD = +2.7V to +5.25V, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC PERFORMANCE (Voltage-Divider Mode, Figure 1) Resolution N 256 Taps Integral Nonlinearity INL (Note 2) 1 LSB Differential Nonlinearity DNL (Note 2) 0.5 LSB 2 LSB Dual-Code Matching End-to-End Resistor Tempco Register A = register B TCR Ratiometric Resistor Tempco Full-Scale Error Zero-Scale Error 35 ppm/C 5 ppm/C MAX5487 3.5 6 MAX5488 -0.6 +1.2 MAX5489 -0.3 +1.2 MAX5487 3.5 6 MAX5488 -0.6 1.5 MAX5489 0.3 1 LSB LSB DC PERFORMANCE (Variable-Resistor Mode, Figure 1) Resolution 256 Integral Nonlinearity (Note 3) Differential Nonlinearity (Note 3) Taps VDD = 5.0V 1.5 VDD = 3.0V 3 VDD = 5.0V 1 VDD = 3.0V 1 LSB LSB DC PERFORMANCE (Resistor Characteristics) Wiper Resistance (Note 4) RW Wiper Capacitance CW End-to-End Resistance RHL www.maximintegrated.com VDD = 5.0V 200 350 VDD = 3.0V 325 675 50 W pF MAX5487 7.5 10 12.5 MAX5488 37.5 50 62.5 MAX5489 75 100 125 kW Maxim Integrated 2 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers DC Electrical Characteristics (continued) (VDD = +2.7V to +5.25V, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DIGITAL INPUTS Input High Voltage (Note 5) VIH Input Low Voltage VIL Input Leakage Current IIN Input Capacitance CIN VDD = 3.6V to 5.25V 2.4 VDD = 2.7V to 3.6V 0.7 x VDD V VDD = 2.7V to 5.25V (Note 5) 0.8 V 1.0 A 5.0 pF -90 dB AC PERFORMANCE Crosstalk fH_ = 1kHz, L_ = GND, measurement at W_ (Note 6) -3dB Bandwidth Wiper at midscale CW_ = 10pF Total Harmonic Distortion BW THD tS 350 MAX5488 90 MAX5489 45 VH_ = 1VRMS at 1kHz, L_ = GND, measurement at W_ TIMING CHARACTERISTICS (Analog) Wiper-Settling Time MAX5487 Code 0 to 127 (Note 7) MAX5487 MAX5488 MAX5489 kHz 0.02 % 0.5 0.75 1.5 s TIMING CHARACTERISTICS (Digital, Figure 2, Note 8) SCLK Frequency 5 MHz SCLK Clock Period tCP 200 ns SCLK Pulse-Width High tCH 80 ns SCLK Pulse-Width Low tCL 80 ns CS Fall to SCLK Rise Setup tCSS 80 ns SCLK Rise to CS Rise Hold tCSH 0 ns DIN to SCLK Setup tDS 50 ns DIN Hold after SCLK tDH 0 ns SCLK Rise to CS Fall Delay tCS0 20 ns CS Rise to SCLK Rise Hold tCS1 80 ns CS Pulse-Width High tCSW 200 ns Write NV Register Busy Time tBUSY 12 ms Read NV Register Access Time tACC 1 s Write Wiper Register to Output Delay tWO 1 s NONVOLATILE MEMORY RELIABILITY Data Retention Endurance www.maximintegrated.com TA = +85C 50 Years TA = +25C 200,000 Stores TA = +85C 50,000 Maxim Integrated 3 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers DC Electrical Characteristics (continued) (VDD = +2.7V to +5.25V, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 5.25 V 400 A 1 A POWER SUPPLIES Power-Supply Voltage VDD Supply Current IDD Standby Current 2.70 During write cycle only, digital inputs = VDD or GND Digital inputs = VDD or GND, TA = +25C 0.5 Note 1: All devices are production tested at TA = +85C and are guaranteed by design and characterization for -40C < TA < +85C. Note 2: DNL and INL are measured with the potentiometer configured as a voltage-divider with H_ = VDD and L_ = 0. The wiper terminal is unloaded and measured with an ideal voltmeter. Note 3: DNL and INL are measured with the potentiometer configured as a variable resistor. H_ is unconnected and L_ = 0. For VDD = +5V, the wiper terminal is driven with a source current of 400A for the 10k configuration, 80A for the 50k configuration, and 40A for the 100k configuration. For VDD = +3V, the wiper terminal is driven with a source current of 200A for the 10k configuration, 40A for the 50k configuration, and 20A for the 100k 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. Note 5: The device draws higher supply current when the digital inputs are driven with voltages between (VDD - 0.5V) and (GND + 0.5V). See Supply Current vs. Digital Input Voltage in the Typical Operating Characteristics section. Note 6: Wiper at midscale with a 10pF load. Note 7: 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 unloaded and measured with a 10pF oscilloscope probe (see Tap-to-Tap Switching Transient in the Typical Operating Characteristics section). Note 8: Digital timing is guaranteed by design and characterization, and is not production tested. www.maximintegrated.com Maxim Integrated 4 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Typical Operating Characteristics (VDD = +5.0V, TA = +25C, unless otherwise noted.) SUPPLY CURRENT (A) 0.4 0.3 0.2 0.1 0 1000 VCC = 5V 100 VCC = 3V 1 VDD = 3V -40 10 250 -20 0 20 40 60 0 80 TEMPERATURE (C) TAP-TO-TAP SWITCHING TRANSIENT (MAX5487) MAX5487-89 toc04 VH_ = 5.0V 200 150 100 50 0 1 2 3 0 5 4 64 96 128 160 192 224 256 TAP-TO-TAP SWITCHING TRANSIENT (MAX5488) TAP-TO-TAP SWITCHING TRANSIENT (MAX5489) MAX5487-89 toc06 VH_ = 5.0V CS 2.0V/div CS 2.0V/div WIPER 20mV/div WIPER 20mV/div 1s/div 32 TAP POSITION MAX5487-89 toc05 WIPER 20mV/div 0 DIGITAL INPUT VOLTAGE (V) VH_ = 5.0V CS 2.0V/div MAX5487-89 toc03 10,000 VDD = 5V 0.5 SUPPLY CURRENT (A) MAX5487-89 toc01 WIPER RESISTANCE vs. TAP POSITION WIPER RESISTANCE () 0.6 SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE MAX5487-89 toc02 SUPPLY CURRENT vs. TEMPERATURE 1.0s/div 1.0s/div MIDSCALE FREQUENCY RESPONSE (MAX5487) WIPER TRANSIENT AT POWER-ON MAX5487-89 toc07 MAX5487-89 toc08 0 VH_ = VDD -2 -4 CW = 10pF -6 GAIN (dB) VDD 2.0V/div -8 CW_ = 50pF -10 -12 -14 WIPER 2.0V/div -16 -18 2.0s/div www.maximintegrated.com -20 0.1 1 10 100 FREQUENCY (kHz) 1000 Maxim Integrated 5 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Typical Operating Characteristics (continued) (VDD = +5.0V, TA = +25C, unless otherwise noted.) -10 -15 CW_ = 50pF -25 -30 -30 -35 -40 -45 -45 -50 1000 100 -0.10 -0.15 0.1 1 10 -0.20 1000 100 0 32 64 128 160 192 224 256 96 TAP POSITION VARIABLE-RESISTOR INL vs. TAP POSITION (MAX5488) VOLTAGE-DIVIDER DNL vs. TAP POSITION (MAX5487) VOLTAGE-DIVIDER INL vs. TAP POSITION (MAX5487) 0.15 0.10 DNL (LSB) 0.2 0 -0.2 1.2 1.0 0.8 0.05 INL (LSB) 0.4 1.4 0 -0.05 -0.4 -0.8 -0.15 -1.0 -0.20 64 96 128 160 192 224 256 0.4 0 32 64 0 32 64 MAx5487-89 toc15 96 128 160 192 224 256 TAP POSITION VOLTAGE-DIVIDER INL vs. TAP POSITION (MAX5488) 1.0 0.8 0.6 0.4 0.05 INL (LSB) DNL (LSB) 0.6 128 160 192 224 256 VOLTAGE-DIVIDER DNL vs. TAP POSITION (MAX5488) 0.10 0 -0.05 0.2 0 -0.2 -0.4 -0.10 -0.6 -0.15 -0.8 0 32 64 96 128 160 192 224 256 TAP POSITION www.maximintegrated.com 96 TAP POSITION 0.15 -0.20 0.2 0.2 TAP POSITION 0.20 0.4 MAx5487-89 toc16 32 0.6 0 -0.10 -0.6 MAX5487-89 toc14 0.20 MAX5487-89 toc13 0.6 INL (LSB) 0 -0.05 FREQUENCY (kHz) 0.8 0 0.05 FREQUENCY (kHz) MAx5487-89 toc12 1.0 10 0.10 -25 -40 1 0.15 CW_ = 50pF -20 -35 0.1 0.20 DNL (LSB) -20 -50 CW_ = 10pF -10 GAIN (dB) GAIN (dB) -15 0 -5 VARIABLE-RESISTOR DNL vs. TAP POSITION (MAX5488) MAx5487-89 toc11 CW_ = 10pF MAX5487-89 toc09 0 -5 MIDSCALE FREQUENCY RESPONSE (MAX5489) MAX5487-89 toc10 MIDSCALE FREQUENCY RESPONSE (MAX5488) -1.0 0 32 64 96 128 160 192 224 256 TAP POSITION Maxim Integrated 6 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Typical Operating Characteristics (continued) (VDD = +5.0V, TA = +25C, unless otherwise noted.) 0.10 0.8 0.6 0 -0.2 64 96 -1.0 128 160 192 224 256 0 32 64 96 0 32 64 128 160 192 224 256 96 VOLTAGE-DIVIDER INL vs. TAP POSITION (MAX5489) CROSSTALK vs. FREQUENCY END-TO-END RESISTANCE CHANGE vs. TEMPERATURE (MAX5487) 0.6 -40 CROSSTALK (dB) 0.4 0.2 0 -0.2 -0.4 CW_ = 10pF MAX5489 MAX5488 -50 -60 MAX5487 -70 -80 -0.6 -90 64 96 128 160 192 224 256 0.1 1 TAP POSITION RESISTANCE CHANGE (%) 0.008 0.006 0.004 0.002 0 -0.002 -0.004 -0.006 -0.008 -0.010 0.004 0.002 0 -0.002 -0.004 -0.006 1000 -0.010 -40 -15 10 35 60 85 TEMPERATURE (C) 0.010 END-TO-END RESISTANCE CHANGE vs. TEMPERATURE (MAX5489) 0.008 0.006 0.004 0.002 0 -0.002 -0.004 -0.006 -0.008 -40 -15 10 35 TEMPERATURE (C) www.maximintegrated.com 10 100 FREQUENCY (kHz) END-TO-END RESISTANCE CHANGE vs. TEMPERATURE (MAX5488) MAX5487-89 toc23 0.010 0.006 -0.008 RESISTANCE CHANGE (%) 32 -100 0.008 MAX5487-89 toc24 -0.8 0.010 RESISTANCE CHANGE (%) -30 MAX5487-89 toc22 TAP POSITION MAX5487-89 toc21 TAP POSITION 0.8 0 -0.20 128 160 192 224 256 TAP POSITION MAx5487-89 toc20 1.0 32 0 -0.05 -0.15 -0.8 0 0.05 -0.10 -0.6 -0.15 INL (LSB) 0.2 -0.4 -0.10 -1.0 0.10 DNL (LSB) INL (LSB) 0 -0.05 -0.20 0.15 0.4 0.05 VOLTAGE-DIVIDER DNL vs. TAP POSITION (MAX5489) 0.20 MAx5487-89 toc18 0.15 DNL (LSB) 1.0 MAx5487-89 toc17 0.20 VARIABLE-RESISTOR INL vs. TAP POSITION (MAX5489) MAx5487-89 toc19 VARIABLE-RESISTOR DNL vs. TAP POSITION (MAX5489) 60 85 -0.010 -40 -15 10 35 60 85 TEMPERATURE (C) Maxim Integrated 7 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers WB LB N.C. TOP VIEW HB Pin Configurations 12 11 10 9 LA 13 WA 14 MAX5487 MAX5488 MAX5489 HA 15 *EP 2 3 4 CS VDD 1 DIN + SCLK I.C. 16 TOP VIEW HA 1 8 I.C. 7 GND 6 N.C. 5 N.C. + 14 VDD WA 2 LA 3 HB 4 WB 5 13 SCLK MAX5487 MAX5488 MAX5489 12 DIN 11 CS 10 N.C. LB 6 9 N.C. N.C. 7 8 GND TSSOP TQFN 3mm x 3mm *EXPOSED PAD. Pin Description PIN NAME FUNCTION TQFN TSSOP 1 14 VDD 2 13 SCLK Serial-Interface Clock Input 3 12 DIN Serial-Interface Data Input Active-Low Chip-Select Digital Input Power Supply. Bypass VDD to GND with a 0.1F capacitor as close to the device as possible. 4 11 CS 5, 6, 9 7, 9, 10 N.C. No Connection. Not internally connected. Ground 7 8 GND 8, 16 -- I.C. Internally connected to EP. Leave unconnected. 10 6 LB Low Terminal of Resistor B. The voltage at L can be greater than or less than the voltage at H. Current can flow into or out of L. 11 5 WB Wiper Terminal of Resistor B 12 4 HB High Terminal of Resistor B. The voltage at H can be greater than or less than the voltage at L. Current can flow into or out of H. 13 3 LA Low Terminal of Resistor A. The voltage at L can be greater than or less than the voltage at H. Current can flow into or out of L. 14 2 WA Wiper Terminal of Resistor A 15 1 HA High Terminal of Resistor A. The voltage at H can be greater than or less than the voltage at L. Current can flow into or out of H. -- -- EP Exposed Pad (TQFN only). Internally connected to pins 8 and 16. Leave unconnected. www.maximintegrated.com Maxim Integrated 8 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Detailed Description The WRITE commands (C1, C0 = 00 or 01) require 16 clock cycles to clock in the command, address, and data (Figure 3a). The COPY commands (C1, C0 = 10, 11) can use either eight clock cycles to transfer only command and address bits (Figure 3b) or 16 clock cycles, with the device disregarding 8 data bits (Figure 3a). After loading data into the shift register, drive CS high to latch the data into the appropriate potentiometer control register and disable the serial interface. Keep CS low during the entire serial data stream to avoid corruption of the data. The MAX5487/MAX5488/MAX5489 contain two resistor arrays, with 255 resistive elements each. The MAX5487 has an end-to-end resistance of 10k, while the MAX5488 and MAX5489 have resistances of 50k and 100k, respectively. These devices allow access to the high, low, and wiper terminals on both potentiometers for a standard voltage-divider configuration. Connect the wiper to the high terminal, and connect the low terminal to ground, to make the device a variable resistor (see Figure 1). A simple 3-wire serial interface programs either wiper directly to any of the 256 tap points. The nonvolatile memory stores the wiper position prior to power-down and recalls the wiper to the same point upon power-up or by using an interface command (see Table 1). The nonvolatile memory is guaranteed for 200,000 wiper store cycles and 50 years for wiper data retention. Digital-Interface Format The data format consists of three elements: command bits, address bits, and data bits (see Table 1 and Figure 3). The command bits (C1 and C0) indicate the action to be taken such as changing or storing the wiper position. The address bits (A1 and A0) specify which potentiometer the command affects and the 8 data bits (D7 to D0) specify the wiper position. SPI Digital Interface These devices use a 3-wire SPI-compatible serial data interface (Figure 2 and Figure 3). This write-only interface contains three inputs: chip-select (CS), data clock (SCLK), and data in (DIN). Drive CS low to enable the serial interface and clock data synchronously into the shift register on each SCLK rising edge. VOLTAGE-DIVIDER CONFIGURATION H VARIABLE-RESISTOR CONFIGURATION H W L L Figure 1. Voltage-Divider/Variable-Resistor Configurations Table 1. Register Map CLOCK EDGE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 -- -- C1 C0 -- -- A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Write Wiper Register A 0 0 0 0 0 0 0 1 D7 D6 D5 D4 D3 D2 D1 D0 Write Wiper Register B 0 0 0 0 0 0 1 0 D7 D6 D5 D4 D3 D2 D1 D0 Write NV Register A 0 0 0 1 0 0 0 1 D7 D6 D5 D4 D3 D2 D1 D0 Write NV Register B 0 0 0 1 0 0 1 0 D7 D6 D5 D4 D3 D2 D1 D0 0 0 1 0 0 0 0 1 -- -- -- -- -- -- -- -- 0 0 1 0 0 0 1 0 -- -- -- -- -- -- -- -- 0 0 1 0 0 0 1 1 -- -- -- -- -- -- -- -- 0 0 1 1 0 0 0 1 -- -- -- -- -- -- -- -- 0 0 1 1 0 0 1 0 -- -- -- -- -- -- -- -- 0 0 1 1 0 0 1 1 -- -- -- -- -- -- -- -- Copy Wiper Register A to NV Register A Copy Wiper Register B to NV Register B Copy Both Wiper Registers to NV Registers Copy NV Register A to Wiper Register A Copy NV Register B to Wiper Register B Copy Both NV Registers to Wiper Registers www.maximintegrated.com Maxim Integrated 9 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers CS tCSW tCSO tCL tCSS tCH tCP tCS1 tCSH SCLK tDS tDH DIN Figure 2. Timing Diagram Write-Wiper Register (Command 00) Write-NV Register (Command 01) Data written to the write-wiper registers (C1, C0 = 00) controls the wiper positions. The 8 data bits (D7 to D0) indicate the position of the wiper. For example, if DIN = 0000 0000, the wiper moves to the position closest to L_. If DIN = 1111 1111, the wiper moves closest to H_. This command (C1, C0 = 01) stores the position of the wipers to the NV registers for use at power-up. Alternatively, the "copy wiper register to NV register" command can be used to store the position of the wipers to the NV registers. Writing to the NV registers does not affect the position of the wipers. This command writes data to the volatile RAM, leaving the NV registers unchanged. When the device powers up, the data stored in the NV registers transfers to the volatile wiper register, moving the wiper to the stored position. Copy Wiper Register to NV Register (Command 10) This command (C1, C0 = 10) stores the current position of the wiper to the NV register, for use at power-up. This command may affect one potentiometer at a time, A) 16-BIT COMMAND/DATA WORD CS SCLK 1 2 DIN 3 4 C1 C0 3 4 C1 C0 5 6 7 8 9 A1 A0 D7 10 D6 11 D5 12 D4 13 D3 14 D2 15 D1 16 D0 B) 8-BIT COMMAND WORD CS SCLK 1 2 DIN 5 6 7 8 A1 A0 Figure 3. Digital-Interface Format www.maximintegrated.com Maxim Integrated 10 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers or both simultaneously, depending on the state of A1 and A0. Alternatively, the "write NV register" command can be used to store the current position of the wiper to the NV register. Copy NV Register to Wiper Register (Command 11) This command (C1, C0 = 11) restores the wiper position to the previously stored position in the NV register. This command may affect one potentiometer at a time, or both simultaneously, depending on the state of A1 and A0. Nonvolatile Memory The internal EEPROM consists of a nonvolatile register that retains the last stored value prior to power-down. The nonvolatile register is programmed to midscale at the factory. The nonvolatile memory is guaranteed for 200,000 wiper write cycles and 50 years for wiper data retention. Power-Up Upon power-up, these devices load the data stored in the nonvolatile wiper register into the volatile memory register, updating the wiper position with the data stored in the nonvolatile wiper register. This initialization period takes 5s. The MAX5487/MAX5488/MAX5489 feature a lowpower standby mode. When the device is not being programmed, it enters into standby mode and supply current drops to 0.5A (typ). Applications Information The MAX5487/MAX5488/MAX5489 are ideal for circuits requiring digitally controlled adjustable resistance, such as LCD contrast control (where voltage biasing adjusts the display contrast), or for programmable filters with adjustable gain and/or cutoff frequency. Positive LCD Bias Control Figure 4 and Figure 5 show an application where the devices provide an adjustable, positive LCD-bias voltage. The op amp provides buffering and gain to the resistordivider network made by the potentiometer (Figure 4) or by a fixed resistor and a variable resistor (Figure 5). Programmable Filter Figure 6 shows the MAX5487/MAX5488/MAX5489 in a 1st-order programmable-filter application. Adjust the gain of the filter with R2, and set the cutoff frequency with R3. Use the following equations to calculate the gain (A) and the -3dB cutoff frequency (fC) 5V H_ MAX5487 MAX5488 MAX5489 Standby 30V W_ MAX480 L_ WA VOUT VIN V+ LA HA R3 C MAX410 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 Figure 4. Positive LCD-Bias Control Using a Voltage-Divider 5V H_ MAX5487 MAX5488 MAX5489 MAX480 R1 HB R2, R3 = RHL x D / 256 WHERE RHL = END-TO-END RESISTANCE AND D = DECIMAL VALUE OF WIPER CODE 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 30V V- VOUT WB R2 LB VOUT Figure 6. Programmable Filter W_ L_ Figure 5. Positive LCD-Bias Control Using a Variable Resistor www.maximintegrated.com Maxim Integrated 11 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers 5V IN VOUT1 OUT HA MAX6160 ADJ 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 WA R GND LA IN OUT 10k FOR THE MAX5487 R 50k VOUT_ = 1.23V x FOR THE MAX5488 R 100k VOUT_ = 1.23V x FOR THE MAX5489 R VOUT_ = 1.23V x VOUT2 HB MAX6160 ADJ GND 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 WB R R2 = RHL x D / 256 WHERE RHL = END-TO-END RESISTANCE AND D = DECIMAL VALUE OF WIPER CODE LB Figure 7. Adjustable Voltage Reference A= 1+ R1 R2 5V WA 1/2 MAX5487/MAX5488/MAX5489 LA HA 1 fC= 2xR 3 x C 3 Offset Voltage and Gain Adjustment Connect the high and low terminals of one potentiometer of a MAX5487/MAX5488/MAX5489 to the NULL inputs of a MAX410, and connect the wiper to the op amp's positive supply to nullify the offset voltage over the operating temperature range. Install the other potentiometer in the feedback path to adjust the gain of the MAX410 (see Figure 8). www.maximintegrated.com 1 MAX410 Adjustable Voltage Reference Figure 7 shows the devices used as the feedback resistors in multiple adjustable voltage-reference applications. Independently adjust the output voltages of the MAX6160s from 1.23V to VIN - 0.2V by changing the wiper positions of the MAX5487/MAX5488/MAX5489. 7 2 4 8 R1 6 R2 = RHL x D / 256 WHERE RHL = END-TO-END RESISTANCE AND = D DECIMAL VALUE OF WIPER CODE HB 1/2 MAX5487/MAX5488/MAX5489 R2 WB LB Figure 8. Offset Voltage and Gain Adjustment Maxim Integrated 12 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Ordering Information END-TO-END RESISTANCE (kW) TOP MARK 16 TQFN-EP* 10 ABR -40C to +85C 14 TSSOP 10 -- -40C to +85C 16 TQFN-EP* 50 ABS MAX5488EUD+ -40C to +85C 14 TSSOP 50 -- MAX5489ETE+ -40C to +85C 16 TQFN-EP* 100 ABT MAX5489EUD+ -40C to +85C 14 TSSOP 100 -- MAX5489ETE/V+ -40C to +85C 16 TQFN-EP* 100 AIE PART TEMP RANGE MAX5487ETE+ -40C to +85C MAX5487EUD+ MAX5488ETE+ PIN-PACKAGE *EP = Exposed pad. +Denotes a lead(Pb)-free/RoHS-compliant package. /V denotes an automotive qualified part. Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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 Chip Information PROCESS: BiCMOS PACKAGE LAND OUTLINE NO. CODE PATTERN NO. 16 TQFN-EP T1633F+3 21-0036 90-0033 14 TSSOP U14+1 21-0066 90-0113 www.maximintegrated.com Maxim Integrated 13 MAX5487/MAX5488/ MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 3 1/07 -- 4 4/10 Updated Ordering Information (added lead-free packaging and automotive qualified part, released TSSOP package), and updated Absolute Maximum Ratings DESCRIPTION 1, 8, 12, 15 1, 2, 12 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated's website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. (c) 2010 Maxim Integrated Products, Inc. 14