19-3478; Rev 4; 4/10 KIT ATION EVALU E L B A IL AVA Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers Features The MAX5487/MAX5488/MAX5489 dual, linear-taper, digital potentiometers function as mechanical potentiometers with a simple 3-wire SPI™-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. o Wiper Position Stored in Nonvolatile Memory (EEPROM) and Recalled Upon Power-Up or Recalled by an Interface Command The MAX5487 has an end-to-end resistance of 10kΩ, while the MAX5488 and MAX5489 have resistances of 50kΩ and 100kΩ, respectively. These devices have a low 35ppm/°C end-to-end temperature coefficient, and operate from a single +2.7V to +5.25V supply. 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 -40°C to +85°C temperature range. o 256 Tap Positions Applications LCD Screen Adjustment Audio Volume Control o 3mm x 3mm x 0.8mm, 16-Pin TQFN or 14-Pin TSSOP Packages o ±1 LSB INL, ±0.5 LSB DNL (Voltage-Divider Mode) o 35ppm/°C End-to-End Resistance Temperature Coefficient o 5ppm/°C Ratiometric Temperature Coefficient o 10kΩ, 50kΩ, and 100kΩ End-to-End Resistance Values o SPI-Compatible Serial Interface o Reliability 200,000 Wiper Store Cycles 50-Year Wiper Data Retention Mechanical Potentiometer Replacement o +2.7V to +5.25V Single-Supply Operation Low-Drift Programmable Filters SPI is a trademark of Motorola, Inc. Low-Drift Programmable-Gain Amplifiers Ordering Information END-TO-END RESISTANCE (kΩ) TOP MARK 16 TQFN-EP* 10 ABR 14 TSSOP 10 — PART TEMP RANGE PIN-PACKAGE MAX5487ETE+ -40°C to +85°C MAX5487EUD+ -40°C to +85°C *EP = Exposed pad. +Denotes a lead(Pb)-free/RoHS-compliant package. Pin Configurations Ordering Information continued at end of data sheet. HA VDD 256 8 8-BIT LATCH DECODER WA SCLK WA 14 HA 15 WB LB N.C. 11 10 9 MAX5487 MAX5488 MAX5489 8 I.C. 7 GND 6 N.C. 5 N.C. LA 16-BIT NV RAM POR I.C. 16 *EP + 1 256 8 DECODER MAX5487 MAX5488 MAX5489 WB 2 3 4 CS 8-BIT LATCH DIN HB CS SCLK DIN SPI INTERFACE 13 12 VDD GND LA HB TOP VIEW Functional Diagram TQFN 3mm x 3mm LB *EXPOSED PAD. Pin Configurations continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX5487/MAX5488/MAX5489 General Description 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 = +70°C) 16-Pin TQFN (derate 17.5mW/°C above +70°C) ..........1398mW 14-Pin TSSOP (derate 9.1mW/°C above +70°C).............727mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-60°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C 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 = -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25°C, 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 Dual-Code Matching End-to-End Resistor Tempco Register A = register B 2 TCR 35 Ratiometric Resistor Tempco 5 Full-Scale Error Zero-Scale Error LSB ppm/°C 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 2 VDD = 5.0V 200 350 VDD = 3.0V 325 675 50 pF MAX5487 7.5 10 12.5 MAX5488 37.5 50 62.5 MAX5489 75 100 125 _______________________________________________________________________________________ Ω kΩ Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers (VDD = +2.7V to +5.25V, VH = VDD, VL = GND, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25°C, 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 µA 5.0 pF -90 dB AC PERFORMANCE fH_ = 1kHz, L_ = GND, measurement at W_ (Note 6) Crosstalk MAX5487 -3dB Bandwidth BW Total Harmonic Distortion THD Wiper at midscale CW_ = 10pF 350 MAX5488 90 MAX5489 45 VH_ = 1VRMS at 1kHz, L_ = GND, measurement at W_ kHz 0.02 % TIMING CHARACTERISTICS (Analog) Wiper-Settling Time tS Code 0 to 127 (Note 7) MAX5487 0.5 MAX5488 0.75 MAX5489 1.5 µs 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 ns tCSH 0 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 µs Write Wiper Register to Output Delay tWO 1 µs NONVOLATILE MEMORY RELIABILITY Data Retention Endurance TA = +85°C 50 TA = +25°C 200,000 TA = +85°C 50,000 Years Stores _______________________________________________________________________________________ 3 MAX5487/MAX5488/MAX5489 DC ELECTRICAL CHARACTERISTICS (continued) 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 = -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 5.25 V 400 µA 1 µA 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 = +25°C 0.5 Note 1: All devices are production tested at TA = +85°C and are guaranteed by design and characterization for -40°C < TA < +85°C. 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 400µA for the 10kΩ configuration, 80µA for the 50kΩ configuration, and 40µA for the 100kΩ configuration. For VDD = +3V, the wiper terminal is driven with a source current of 200µA for the 10kΩ configuration, 40µA for the 50kΩ configuration, and 20µA for the 100kΩ 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. VOLTAGE-DIVIDER CONFIGURATION H VARIABLE-RESISTOR CONFIGURATION H W L L Figure 1. Voltage-Divider/Variable-Resistor Configurations 4 _______________________________________________________________________________________ Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers SUPPLY CURRENT vs. TEMPERATURE 0.3 0.2 0.1 200 VCC = 5V 100 10 VCC = 3V 1 VDD = 3V 0 -20 0 20 40 60 80 TAP-TO-TAP SWITCHING TRANSIENT (MAX5487) 100 0 0 TEMPERATURE (°C) 150 50 0 -40 1 2 3 0 5 4 32 64 96 128 160 192 224 256 DIGITAL INPUT VOLTAGE (V) TAP POSITION TAP-TO-TAP SWITCHING TRANSIENT (MAX5488) TAP-TO-TAP SWITCHING TRANSIENT (MAX5489) MAX5487-89 toc04 MAX5487-89 toc06 MAX5487-89 toc05 VH_ = 5.0V VH_ = 5.0V VH_ = 5.0V MAX5487-89 toc03 1000 0.4 250 WIPER RESISTANCE (Ω) VDD = 5V SUPPLY CURRENT (µA) CS 2.0V/div WIPER 20mV/div CS 2.0V/div CS 2.0V/div WIPER 20mV/div WIPER 20mV/div 1.0µs/div 1.0µs/div 1µs/div MIDSCALE FREQUENCY RESPONSE (MAX5487) WIPER TRANSIENT AT POWER-ON MAX5487-89 toc07 MAX5487-89 toc08 0 VH_ = VDD -2 -4 VDD 2.0V/div CW = 10pF -6 GAIN (dB) SUPPLY CURRENT (µA) 10,000 MAX5487-89 toc02 MAX5487-89 toc01 0.6 0.5 WIPER RESISTANCE vs. TAP POSITION SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE -8 CW_ = 50pF -10 -12 -14 WIPER 2.0V/div -16 -18 -20 2.0µs/div 0.1 1 10 100 FREQUENCY (kHz) 1000 _______________________________________________________________________________________ 5 MAX5487/MAX5488/MAX5489 Typical Operating Characteristics (VDD = +5.0V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VDD = +5.0V, TA = +25°C, unless otherwise noted.) MIDSCALE FREQUENCY RESPONSE (MAX5488) MIDSCALE FREQUENCY RESPONSE (MAX5489) CW_ = 10pF -10 -15 -20 -25 -30 -25 -30 -35 -40 -40 -45 -45 -50 0.15 0.10 CW_ = 50pF -20 -35 0.20 1 10 1000 100 0 -0.05 -0.10 -0.15 -50 0.1 0.05 DNL (LSB) CW_ = 50pF GAIN (dB) -0.20 0.1 1 10 1000 100 0 32 64 96 128 160 192 224 256 FREQUENCY (kHz) FREQUENCY (kHz) TAP POSITION VARIABLE-RESISTOR INL vs. TAP POSITION (MAX5488) VOLTAGE-DIVIDER DNL vs. TAP POSITION (MAX5487) VOLTAGE-DIVIDER INL vs. TAP POSITION (MAX5487) 0.8 0.6 1.4 0.15 0.10 MAX5487-89 toc14 0.20 MAx5487-89 toc12 1.0 MAX5487-89 toc13 GAIN (dB) -15 0 -5 MAx5487-89 toc11 -10 VARIABLE-RESISTOR DNL vs. TAP POSITION (MAX5488) MAX5487-89 toc10 CW_ = 10pF MAX5487-89 toc09 0 -5 1.2 1.0 0.8 0.2 0 -0.2 0.05 INL (LSB) DNL (LSB) 0.4 INL (LSB) 0 -0.05 -0.4 -0.8 -0.15 -1.0 -0.20 0 32 64 96 0.4 0.2 0.2 0.4 0.6 0 128 160 192 224 256 0.6 0 -0.10 -0.6 32 64 96 0 128 160 192 224 256 32 0.10 128 160 192 224 256 MAx5487-89 toc16 1.0 MAx5487-89 toc15 0.15 96 VOLTAGE-DIVIDER INL vs. TAP POSITION (MAX5488) VOLTAGE-DIVIDER DNL vs. TAP POSITION (MAX5488) 0.20 64 TAP POSITION TAP POSITION TAP POSITION 0.8 0.6 0.4 0.05 INL (LSB) DNL (LSB) MAX5487/MAX5488/MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers 0 -0.05 0.2 0 -0.2 -0.4 -0.10 -0.6 -0.15 -0.8 -1.0 -0.20 0 32 64 96 128 160 192 224 256 TAP POSITION 6 0 32 64 96 128 160 192 224 256 TAP POSITION _______________________________________________________________________________________ Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers VARIABLE-RESISTOR DNL vs. TAP POSITION (MAX5489) 0.10 0.8 0.20 0.6 0.15 0.10 0 -0.05 0.2 DNL (LSB) INL (LSB) 0 -0.2 -0.10 -0.6 -0.15 -1.0 32 64 128 160 192 224 256 96 -0.20 0 32 64 96 128 160 192 224 256 0 32 64 96 128 160 192 224 256 TAP POSITION TAP POSITION TAP POSITION VOLTAGE-DIVIDER INL vs. TAP POSITION (MAX5489) CROSSTALK vs. FREQUENCY END-TO-END RESISTANCE CHANGE vs. TEMPERATURE (MAX5487) 0.8 0.6 CW_ = 10pF -40 CROSSTALK (dB) 0.4 0.2 0 -0.2 -0.4 MAX5489 MAX5488 -50 -60 MAX5487 -70 -80 0.010 0.008 RESISTANCE CHANGE (%) -30 MAx5487-89 toc20 1.0 MAX5487-89 toc21 0 -0.6 0.006 0.004 0.002 0 -0.002 -0.004 -0.006 -90 -0.8 -1.0 -0.008 -100 64 96 128 160 192 224 256 -0.010 0.1 1 TAP POSITION 10 100 FREQUENCY (kHz) 1000 0.008 0.006 -15 10 35 60 85 END-TO-END RESISTANCE CHANGE vs. TEMPERATURE (MAX5489) 0.004 0.002 0 -0.002 -0.004 0.010 MAX5487-89 toc24 0.010 -40 TEMPERATURE (°C) END-TO-END RESISTANCE CHANGE vs. TEMPERATURE (MAX5488) 0.008 RESISTANCE CHANGE (%) 32 MAX5487-89 toc23 0 RESISTANCE CHANGE (%) INL (LSB) -0.15 -0.8 -0.20 0 -0.05 -0.4 -0.10 0.05 MAX5487-89 toc22 DNL (LSB) 0.4 0.05 MAx5487-89 toc19 0.15 VOLTAGE-DIVIDER DNL vs. TAP POSITION (MAX5489) MAx5487-89 toc18 1.0 MAx5487-89 toc17 0.20 VARIABLE-RESISTOR INL vs. TAP POSITION (MAX5489) 0.006 0.004 0.002 0 -0.002 -0.004 -0.006 -0.006 -0.008 -0.008 -0.010 -0.010 -40 -15 10 35 TEMPERATURE (°C) 60 85 -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 7 MAX5487/MAX5488/MAX5489 Typical Operating Characteristics (continued) (VDD = +5.0V, TA = +25°C, unless otherwise noted.) Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers MAX5487/MAX5488/MAX5489 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 0.1µF capacitor as close to the device as possible. 4 11 CS 5, 6, 9 7, 9, 10 N.C. No Connection. Not internally connected. 7 8 GND Ground 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. Detailed Description The MAX5487/MAX5488/MAX5489 contain two resistor arrays, with 255 resistive elements each. The MAX5487 has an end-to-end resistance of 10kΩ, while the MAX5488 and MAX5489 have resistances of 50kΩ and 100kΩ, respectively. The MAX5487/MAX5488/MAX5489 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. SPI Digital Interface The MAX5487/MAX5488/MAX5489 use a 3-wire SPIcompatible serial data interface (Figures 2 and 3). This write-only interface contains three inputs: chip-select 8 (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. 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. 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. _______________________________________________________________________________________ Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers 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 Copy Wiper Register A to NV Register A 0 0 1 0 0 0 0 1 — — — — — — — — Copy Wiper Register B to NV Register B 0 0 1 0 0 0 1 0 — — — — — — — — Copy Both Wiper Registers to NV Registers 0 0 1 0 0 0 1 1 — — — — — — — — Copy NV Register A to Wiper Register A 0 0 1 1 0 0 0 1 — — — — — — — — Copy NV Register B to Wiper Register B 0 0 1 1 0 0 1 0 — — — — — — — — Copy Both NV Registers to Wiper Registers 0 0 1 1 0 0 1 1 — — — — — — — — CLOCK EDGE CS tCSW tCSO tCSS tCL tCH tCP tCSH tCS1 SCLK tDS tDH DIN Figure 2. Timing Diagram Write-Wiper Register (Command 00) 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 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. Write-NV Register (Command 01) 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. 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, _______________________________________________________________________________________ 9 MAX5487/MAX5488/MAX5489 Table 1. Register Map MAX5487/MAX5488/MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers 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 DIN 2 5 6 7 8 A1 A0 Figure 3. Digital-Interface Format 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, the MAX5487/MAX5488/MAX5489 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 5µs. 10 Standby The MAX5487/MAX5488/MAX5489 feature a low-power standby mode. When the device is not being programmed, it enters into standby mode and supply current drops to 0.5µA (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 Figures 4 and 5 show an application where the MAX5487/MAX5488/MAX5489 provide an adjustable, positive LCD-bias voltage. The op amp provides buffering and gain to the resistor-divider 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. ______________________________________________________________________________________ Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers H_ 30V A =1+ W_ MAX5487 MAX5488 MAX5489 VOUT MAX480 R1 R2 L_ fC = 1 2π × R3 × C Adjustable Voltage Reference Figure 4. Positive LCD-Bias Control Using a Voltage-Divider Figure 7 shows the MAX5487/MAX5488/MAX5489 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. 5V 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). 30V H_ VOUT MAX480 MAX5487 MAX5488 MAX5489 W_ L_ Chip Information PROCESS: BiCMOS Figure 5. Positive LCD-Bias Control Using a Variable Resistor Pin Configurations (continued) WA TOP VIEW V+ VIN LA HA R3 HA 1 C MAX410 VOUT + 14 VDD WA 2 13 SCLK LA 3 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 VR1 WB 5 HB R2, R3 = RHL x D / 256 WHERE RHL = END-TO-END RESISTANCE AND D = DECIMAL VALUE OF WIPER CODE 12 DIN MAX5487 MAX5488 MAX5489 11 CS 10 N.C. LB 6 9 N.C. N.C. 7 8 GND WB R2 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 HB 4 TSSOP LB Figure 6. Programmable Filter ______________________________________________________________________________________ 11 MAX5487/MAX5488/MAX5489 Use the following equations to calculate the gain (A) and the -3dB cutoff frequency (fC): 5V MAX5487/MAX5488/MAX5489 Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers 5V IN IN V OUT1 OUT OUT 10kΩ FOR THE MAX5487 R 50kΩ VOUT_ = 1.23V x FOR THE MAX5488 R 100kΩ VOUT_ = 1.23V x FOR THE MAX5489 R VOUT_ = 1.23V x VOUT2 HB HA MAX6160 MAX6160 ADJ 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 WA R GND ADJ R GND LA 1/2 MAX5487 1/2 MAX5488 1/2 MAX5489 WB R2 = RHL x D / 256 WHERE RHL = END-TO-END RESISTANCE AND D = DECIMAL VALUE OF WIPER CODE LB Figure 7. Adjustable Voltage Reference Package Information 5V 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. WA 1/2 MAX5487/MAX5488/MAX5489 LA HA 7 3 1 PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 16 TQFN-EP T1633F+3 21-0136 90-0033 14 TSSOP U14+1 21-0066 90-0113 8 6 MAX410 2 4 R1 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 Ordering Information (continued) END-TO-END RESISTANCE (kΩ) TOP MARK 16 TQFN-EP* 50 ABS 14 TSSOP 50 — 16 TQFN-EP* 100 ABT PART TEMP RANGE PIN-PACKAGE MAX5488ETE+ -40°C to +85°C MAX5488EUD+ -40°C to +85°C MAX5489ETE+ -40°C to +85°C MAX5489EUD+ -40°C to +85°C 14 TSSOP 100 — MAX5489ETE/V+ -40°C to +85°C 16 TQFN-EP* 100 AIE *EP = Exposed pad. +Denotes a lead(Pb)-free/RoHS-compliant package. /V denotes an automotive qualified part. 12 ______________________________________________________________________________________ Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers REVISION NUMBER REVISION DATE 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 PAGES CHANGED 1, 8, 12, 15 1, 2, 12 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 ____________________ 13 © 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX5487/MAX5488/MAX5489 Revision History