MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer General Description Features The MAX5394 single, 256-tap volatile, low-voltage linear taper digital potentiometer offers three end-toend resistance values of 10kΩ, 50kΩ, and 100kΩ. Potentiometer terminals are independent of supply for voltages up to 5.25V with single-supply operation from 1.7V to 5.5V (charge pump enabled). User-controlled shutdown modes allow the H, W, or L terminal to be opened with the wiper position set to zero-code, midcode, full-code, or the value contained in the wiper register. Ultra-low-quiescent supply current (< 1µA) can be achieved for supply voltages between 2.6V and 5.5V by disabling the internal charge pump and not allowing potentiometer terminals to exceed the supply voltage by more than 0.3V. The MAX5394 provides a low 50ppm/°C end-to-end temperature coefficient and features a SPI serial interface. SSingle Linear Taper 256-Tap Positions S10kI, 50kI, and 100kI End-to-End Resistance S1.7V to 5.5V Extended Single Supply S0 to 5.25V H, W, L Operating Voltage Independent of VDD S1µA (typ) Supply Current in Low-Power Mode S±1.0 LSB INL, ±0.5 LSB DNL (max) Wiper Accuracy SPower-On Sets Wiper to Midscale S50ppm/NC End-to-End Temperature Coefficient S5ppm/NC Ratiometric Temperature Coefficient S-40NC to +125NC Operating Temperature Range S2mm x 2mm, 8-Pin TDFN Package SSPI-Compatible Serial Interface The small package size, low operating supply voltage, low supply current, and automotive temperature range of the MAX5394 make the device uniquely suited for the portable consumer market, battery-backup industrial applications, and automotive market. Applications Portable Electronics System Calibration The MAX5394 is available in a lead-free, 8-pin TDFN (2mm x 2mm) package. The device operates over the -40°C to +125°C automotive temperature range. Battery-Powered Systems Automotive Electronics Mechanical Potentiometer Replacement Ordering Information appears at end of data sheet. Typical Operating Circuit VDD 1.7V TO 5.5V (CHARGE PUMP ENABLED) H +5V VS MAX5394 MAX4250 CS W SPI INTERFACE DIN SCLK GND VO L R1 VO / VS = 1 + RMAX5394 /R1 For related parts and recommended products to use with this part, refer to: www.maximintegrated.com/MAX5394.related For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com. 19-6392; Rev 1; 9/12 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Absolute Maximum Ratings (All voltages referenced to GND.) VDD ..........................................................................-0.3V to +6V H, W, L (charge pump enabled) ..........................-0.3V to +5.5V H, W, L (charge pump disabled)................. -0.3V to the lower of (VDD + 0.3V) or +6V All Other Pins ..........................................................-0.3V to +6V Continuous Current into H, W, and L MAX5394L..........................................................................5mA MAX5394M.........................................................................2mA MAX5394N.........................................................................1mA Maximum Current into Any Input........................................50mA Continuous Power Dissipation (TA = +70NC) TDFN (derate 11.9mW/NC above +70NC)..................953.5mW Operating Temperature Range ........................ -40NC to +125NC Storage Temperature Range............................ -65NC to + 150NC Junction Temperature......................................................+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. Package Thermal Characteristics (Note 1) TDFN Junction-to-Ambient Thermal Resistance (qJA)........83.9°C/W Junction-to-Case Thermal Resistance (qJC).............37.0°C/W Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Electrical Characteristics (VDD = 1.7V to 5.5V, VH = VDD, VL = GND, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = 1.8V, TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RESOLUTION 256-Tap Family N 256 Tap DC PERFORMANCE (VOLTAGE-DIVIDER MODE) Integral Nonlinearity (Note 3) INL Differential Nonlinearity DNL (Note 3) Ratiometric Resistor Tempco (DVW/VW)/DT, VH = VDD, VL = GND, no load Full-Scale Error (Code FFh) Charge pump enabled, 1.7V < VDD < 5.5V MAX5394M Charge pump disabled, MAX5394N 2.6V < VDD < 5.5VS MAX5394L -1.0 +1.0 LSB -0.5 +0.5 LSB 5 -0.5 -0.5 Charge pump disabled, 2.6V < VDD < 5.5V LSB -1.0 Charge pump enabled, 1.7V < VDD < 5.5V Zero-Scale Error (Code 00h) ppm/°C +0.5 MAX5394M MAX5394N +0.5 MAX5394L +1.0 LSB DC PERFORMANCE (Variable Resistor ModE) Charge pump enabled, 1.7V < VDD < 5.5V Integral Nonlinearity (Note 4) Maxim Integrated R-INL Charge pump disabled, 2.6V < VDD < 5.5V -1.0 +1.0 MAX5394M MAX5394N -1.0 +1.0 MAX5394L -1.5 +1.5 LSB 2 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer ELECTRICAL CHARACTERISTICS (continued) (VDD = 1.7V to 5.5V, VH = VDD, VL = GND, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = 1.8V, TA = +25°C.) (Note 2) PARAMETER Differential Nonlinearity Wiper Resistance (Note 5) SYMBOL R-DNL RWL CONDITIONS (Note 4) MIN TYP -0.5 Charge pump enabled, 1.7V < VDD < 5.5V Charge pump disabled, 2.6V < VDD < 5.5V 25 MAX UNITS +0.5 LSB 50 200 Ω DC PERFORMANCE (Resistor Characteristics) CH, CL Measured to GND 10 Wiper Capacitance CW Measured to GND 20 pF End-to-End Resistor Tempco TCR No load 50 ppm/°C Terminal Capacitance End-to-End Resistor Tolerance Wiper not connected -25 pF +25 % AC PERFORMANCE -3dB Bandwidth Total Harmonic Distortion Plus Noise Wiper Settling Time Charge-Pump Feedthrough at W BW THD+N tS Code = 80h, 10pF load, VDD = 1.8V 10kΩ 1600 50kΩ 340 100kΩ 165 (Note 6) (Note 7) kHz 0.035 10kΩ 190 50kΩ 400 100kΩ 664 % ns 600 VRW nVRMS POWER SUPPLIES Supply Voltage Range Terminal Voltage Range (H, W, L to GND) Supply Current (Note 8) 1.7 5.5 Charge pump enabled, 1.7V < VDD < 5.5V 0 5.25 Charge pump disabled, 2.6V < VDD < 5.5V Charge pump disabled, 2.6V < VDD < 5.5V 0 VDD VDD IVDD Charge pump enabled, 1.7V < VDD < 5.5V V V 1 VDD = 5.5V 25 VDD = 1.7V 20 µA DIGITAL INPUTS Minimum Input High Voltage VIH 2.6V < VDD < 5.5V 1.7V < VDD < 2.6V Maximum Input Low Voltage VIL 2.6V < VDD < 5.5V 1.7V < VDD < 2.6V Input Leakage Current Input Capacitance Maxim Integrated 70 % x VDD 80 30 20 -1 +1 5 % x VDD µA pF 3 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer ELECTRICAL CHARACTERISTICS (continued) (VDD = 1.7V to 5.5V, VH = VDD, VL = GND, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = 1.8V, TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS TIMING CHARACTERISTICS (Note 9) SCLK Frequency fSCLK SCLK Period tSCLK 2.6V < VDD < 5.5V 50 1.7V < VDD < 2.6V 25 2.6V < VDD < 5.5V 1.7V < VDD < 2.6V 20 40 MHz ns SCLK Pulse-Width High tCH 8 ns SCLK Pulse-Width Low tCL 8 ns CS Fall to SCLK Fall Setup Time tCSS0 To 1st SCLK falling edge (FE) 2.6V < VDD < 5.5V 8 1.7V < VDD < 2.6V 16 CS Fall to SCLK Fall Hold Time tCSH0 Applies to inactive FE preceding 1st FE 0 ns CS Rise to SCLK Fall Hold Time tCSH1 Applies to 16th FE 0 ns CS Rise to SCLK Fall tCSA Applies to 16th FE, aborted sequence SCLK Fall to CS Fall tCSF Applies to 16th FE 100 ns CS Pulse-Width High tCSPW 20 ns tDS 5 ns tDH 4.5 ns tCSPW 20 ns DIN to SCLK Fall Setup Time DIN to SCLK Fall Hold Time CS Pulse-Width High 2.6V < VDD < 5.5V 12 1.7V < VDD < 2.6V 16 ns ns Note 2: All devices are production tested at TA = +25°C and are guaranteed by design and characterization for TA = -40°C to +125°C. Note 3: DNL and INL are measured with the potentiometer configured as a voltage-divider with VH = 5.25 (QP enabled) or VDD (QP disabled) and VL = GND. The wiper terminal is unloaded and measured with an ideal voltmeter. Note 4: R-DNL and R-INL are measured with the potentiometer configured as a variable resistor (Figure 1). H is unconnected and L = GND. For charge pump enabled, VDD = 1.7V to 5.5V, 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 charge pump disabled and VDD = 5.5V, 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 charge pump disabled and VDD = +2.6V, 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 5: The wiper resistance is the maximum value measured by injecting the currents given in Note 4 into W with L = GND. RW = (VW - VH)/IW. Note 6: Measured at W with H driven with a 1kHz, 0V to VDD amplitude tone and VL = GND. 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 loaded with 10pF capacitance to ground. Note 8: Digital inputs at VDD or GND. Note 9: Digital timing is guaranteed by design and characterization, and is not production tested. Maxim Integrated 4 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer H N.C. W W L L Figure 1. Voltage-Divider and Variable Resistor Configurations DIN15 DIN DIN14 DIN13 1 tCSH0 2 tCSS0 DIN11 tDH tDS SCLK DIN12 3 4 DIN9 DIN8 7 8 DIN2 DIN1 DIN0 DIN15 tCP 5 tCH DIN10 6 tCL 14 15 tCSA 16 1 tCSH1 CS tCSPW tCSF Figure 2. SPI Timing Diagram Maxim Integrated 5 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Typical Operating Characteristics SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE 25 20 15 10 5 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 VDD = 1.8V (LOW-HIGH) 25 20 15 5 0 0 1 2 3 4 5 1.70 4.55 5.50 RESISTANCE (W-TO-L) vs. TAP POSITION (100kI) 4 3 100 40 90 W-TO-L RESISTANCE (kI) W-TO-L RESISTANCE (kI) 45 35 30 25 20 15 80 70 60 50 40 30 2 10 20 1 5 10 0 0 64 96 128 160 192 224 256 MAX5394 toc06 50 MAX5394 toc04 5 0 0 32 64 96 128 160 192 224 256 0 32 64 96 128 160 192 224 256 TAP POSITION WIPER RESISTANCE vs. WIPER VOLTAGE WIPER RESISTANCE vs. WIPER VOLTAGE END-TO-END RESISTANCE PERCENTAGE CHANGE vs. TEMPERATURE WIPER RESISTANCE (I) VDD = 5V, QP OFF 35 VDD = 1.8V, QP ON 30 25 20 15 10 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) Maxim Integrated 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V) 0.8 MAX5394 toc08 MAX5394 toc07a 40 END-TO-END RESISTANCE PERCENTAGE CHANGE (%) TAP POSITION MAX5394 toc07b TAP POSITION VDD = 2.6V, QP OFF 0 3.60 RESISTANCE (W-TO-L) vs. TAP POSITION (50kI) 6 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 2.65 RESISTANCE (W-TO-L) vs. TAP POSITION (10kI) 7 32 TA = -40°C 10 INPUT VOLTAGE (V) 8 0 TA = +25°C 30 DIGITAL INPUT VOLTAGE (V) 9 W-TO-L RESISTANCE (kI) VDD = 3.3V (HIGH-LOW) TA = +125°C TEMPERATURE (°C) 10 WIPER RESISTANCE (I) VDD = 5V (HIGH-LOW) VDD = 1.8V (HIGH-LOW) 35 SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 30 VDD = 5V (LOW-HIGH) VDD = 3.3V (LOW-HIGH) SUPPLY CURRENT vs. INPUT VOLTAGE 40 MAX5394 toc02 VDD = 1.8V 35 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 0 MAX5394 toc05 40 MAX5394 toc01 SUPPLY CURRENT vs. TEMPERATURE MAX5394 toc03 (VDD = 1.8V, TA = +25NC, unless otherwise noted.) 0.6 100kI 0.4 0.2 50kI 0 10kI -0.2 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) 6 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Typical Operating Characteristics (continued) (VDD = 1.8V, TA = +25NC, unless otherwise noted.) TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128 10kI) TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128 50kI) MAX5394 toc09 MAX5394 toc10 VW-L 10mV/div VW-L 10mV/div VSCLK 2V/div VSCLK 2V/div 200ns/div 200ns/div TAP-TO-TAP SWITCHING TRANSIENT (CODE 127 TO 128 100kI) POWER-ON TRANSIENT (10kI) MAX5394 toc11 MAX5394 toc12a VW-L 1V/div VW-L 10mV/div VDD 1V/div VSCLK 2V/div 200ns/div 10µs/div POWER-ON TRANSIENT (50kI) POWER-ON TRANSIENT (100kI) MAX5394 toc12b MAX5394 toc12c VW-L 1V/div VW-L 1V/div VDD 1V/div VDD 1V/div 10µs/div Maxim Integrated 10µs/div 7 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Typical Operating Characteristics (continued) (VDD = 1.8V, TA = +25NC, unless otherwise noted.) MAX5394 toc14 10 0 -10 0 VDD = 5V GAIN (dB) GAIN (dB) 0 GAIN (dB) MIDSCALE FREQUENCY RESPONSE (100kI) 10 MAX5394 toc13 10 MIDSCALE FREQUENCY RESPONSE (50kI) MAX5394 toc15 MIDSCALE FREQUENCY RESPONSE (10kI) -10 VDD = 5V -10 VDD = 5V -20 VDD = 1.8V -20 VIN = 1VP-P CW = 10pF -30 0.01k 0.1k VIN = 1VP-P CW = 10pF 1k 10k 100k 1M 10M 1k 10k 100k 1M 10M 0.1k VDD = 1.8V 1k 10k 100k 1M FREQUENCY (Hz) FREQUENCY (Hz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY CHARGE-PUMP FEEDTHROUGH AT W VARIABLE-RESISTOR DNL vs. TAP POSITION (10kI) 0.12 0.10 50kI 50kI 100kI 0.3 700 0.2 10kI 600 500 400 0.1 0 -0.1 300 -0.2 0.04 200 -0.3 0.02 100 -0.4 0.06 100kI 0 0.1 1 0 10 1.00 1.25 1.50 1.75 -0.5 2.00 0 96 128 160 192 224 256 VARIABLE-RESISTOR DNL vs. TAP POSITION (50kI) VARIABLE-RESISTOR DNL vs. TAP POSITION (100kI) VARIABLE-RESISTOR INL vs. TAP POSITION (10kI) VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.4 0.3 0.5 MAX5394 toc18c 0.5 0.3 0.1 0.1 -0.1 INL (LSB) 0.1 DNL (LSB) 0.2 0 0 -0.1 0 -0.1 -0.2 -0.2 -0.2 -0.3 -0.3 -0.3 -0.4 -0.4 -0.4 -0.5 -0.5 64 96 128 160 192 224 256 TAP POSITION Maxim Integrated VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF 0.4 0.2 32 64 TAP POSITION 0.2 0 32 FREQUENCY (MHz) VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.3 0.75 FREQUENCY (kHz) 0.5 0.4 0.50 100 MAX5394 toc18b 0.01 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.4 10M MAX5394 toc19a 10kI 0.08 800 VOLTAGE (nVRMS) 0.14 900 DNL (LSB) 0.16 0.5 MAX5394 toc17 1000 MAX5394 toc16 0.18 THD+N (%) 0.1k -30 0.01k FREQUENCY (Hz) 0.20 DNL (LSB) -30 0.01k VIN = 1VP-P CW = 10pF VDD = 1.8V MAX5394 toc18a -20 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF -0.5 0 32 64 96 128 160 192 224 256 TAP POSITION 0 32 64 96 128 160 192 224 256 TAP POSITION 8 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer 0.4 0.3 INL (LSB) 0.1 0 -0.1 -0.2 -0.3 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF -0.4 -0.5 0.2 0.1 0.1 -0.1 64 96 -0.2 -0.3 -0.3 -0.4 -0.4 128 160 192 224 256 96 128 160 192 224 256 0 96 128 160 192 224 256 VOLTAGE-DIVIDER DNL vs. TAP POSITION (50kI) VOLTAGE-DIVIDER DNL vs. TAP POSITION (100kI) VOLTAGE-DIVIDER INL vs. TAP POSITION (10kI) VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.4 0.3 0.5 MAX5394 toc20c 0.5 0.3 0.1 -0.1 INL (LSB) 0.1 DNL (LSB) 0.2 0.1 0 0 -0.1 0 -0.1 -0.2 -0.2 -0.2 -0.3 -0.3 -0.3 -0.4 -0.4 -0.4 -0.5 -0.5 64 96 128 160 192 224 256 -0.5 0 32 TAP POSITION 64 96 96 128 160 192 224 256 TAP POSITION 0.5 MAX5394 toc21b VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.3 0.2 0.2 0.1 0.1 0 -0.1 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.4 INL (LSB) INL (LSB) 64 VOLTAGE-DIVIDER INL vs. TAP POSITION (100kI) 0 -0.1 -0.2 -0.2 -0.3 -0.3 -0.4 -0.4 -0.5 -0.5 0 32 64 96 128 160 192 224 256 TAP POSITION Maxim Integrated 32 TAP POSITION 0.5 0.3 0 128 160 192 224 256 VOLTAGE-DIVIDER INL vs. TAP POSITION (50kI) 0.4 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.4 0.2 32 64 TAP POSITION 0.2 0 32 TAP POSITION VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.3 64 TAP POSITION 0.5 0.4 -0.5 32 0 MAX5394 toc20b 32 0 -0.1 -0.2 -0.5 0 DNL (LSB) 0.3 0.2 0 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF 0.4 MAX5394 toc21a VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF 0.2 0.5 MAX5394 toc21c 0.3 VDD = 1.8V, VH = 5.0V, CHARGE PUMP ON VDD = 2.6V, VH = 2.6V, CHARGE PUMP OFF VDD = 5.0V, VH = 5.0V, CHARGE PUMP OFF DNL (LSB) 0.4 INL (LSB) 0.5 MAX5394 toc19b 0.5 VOLTAGE-DIVIDER DNL vs. TAP POSITION (10kI) MAX5394 toc20a VARIABLE-RESISTOR INL vs. TAP POSITION (100kI) MAX5394 toc19c VARIABLE-RESISTOR INL vs. TAP POSITION (50kI) 0 32 64 96 128 160 192 224 256 TAP POSITION 9 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Pin Configuration TOP VIEW 1 GND 2 CS 3 DIN 4 + L MAX5394 EP 8 H 7 W 6 VDD 5 SCLK TDFN Pin Description PIN NAME 1 L FUNCTION Low Terminal. The voltage at L can be greater than or less than the voltage at H. Current can flow into or out of L. 2 GND 3 CS Ground Active-Low Chip-Select Digital Input 4 DIN Serial-Interface Data Input Serial-Interface Clock Input 5 SCLK 6 VDD Power Supply 7 W Wiper Terminal 8 H High Terminal. 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. Internally connected to GND. Connected to ground. Maxim Integrated 10 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Functional Diagram portable consumer market, battery-backup industrial applications, and automotive market. Charge Pump The MAX5394 contains an internal charge pump that guarantees the maximum wiper resistance, RWL, to be less than 50Ω (25Ω typ) for supply voltages down to 1.7V and allows pins H, W, and L to be driven between GND and 5.25V independent of VDD. Minimal chargepump feedthrough is present at the terminal outputs and is illustrated by the Charge-Pump Feedthrough at W vs. Frequency graph in the Typical Operating Characteristics. The charge pump is on by default but can be disabled with QP_OFF and enabled with the QP_ON commands (Table 1). The MAX5394 minimum supply voltage with charge pump disabled is limited to 2.6V and terminal voltage cannot exceed -0.3V to (VDD + 0.3V). MAX5394 L H GND W VDD CS SCLK SPI INTERFACE DIN Detailed Description The MAX5394 single, 256-tap volatile, low-voltage linear taper digital potentiometer offers three end-toend resistance values of 10kΩ, 50kΩ, and 100kΩ. Potentiometer terminals are independent of supply for voltages up to +5.25V with single-supply operation from 1.7V to 5.5V (charge pump enabled). User-controlled shutdown modes allow the H, W, or L terminals to be opened with the wiper position set to zero-code, midcode, full-code, or the value contained in the wiper register. Ultra-low-quiescent supply current (< 1µA) can be achieved for supply voltages between 2.6V and 5.5V by disabling the internal charge pump and not allowing potentiometer terminals to exceed the supply voltage by more than 0.3V. The MAX5394 provides a low 50ppm/°C end-to-end temperature coefficient and features a SPI serial interface. SPI Interface The digital interface is powered from VDD, not the internal charge-pump voltage. Therefore the VIH and VIL logic thresholds will follow VDD as specified in the Electrical Characteristics table. The SPI digital interface uses a 3-wire serial data interface to control the wiper tap position. This write-only interface contains three inputs: Chip Select (CS), Data In (DIN), and Data Clock (SCLK). When CS is taken low, data from the DIN pin is synchronously loaded into the serial shift register on each falling edge of each SCLK pulse (Figure 3). After all the data bits have been shifted in, they are latched into the potentiometer control register. Data written to a memory register immediately updates the wiper position. Keep CS low during the entire data stream to prevent the data from being terminated. The power-on default position of the wiper is midscale (D[7:0] = 80H). The small package size, low supply operating voltage, low supply current, and automotive temperature range of the MAX5394 make the device uniquely suited for the CS SCLK DIN C7 C6 C5 C4 C3 C2 C1 C0 D7 D6 D5 D4 D3 D2 D1 D0 WIPER REGISTER LOADED Figure 3. SPI Digital Interface Format Maxim Integrated 11 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Table 1. SPI Write Command Byte Summary COMMAND COMMAND BYTE DATA BYTE C7 C6 C5 C4 C3 C2 C1 C0 D7 D6 D5 D4 D3 D2 D1 D0 WIPER 0 0 0 0 0 0 0 0 D7 D6 D5 D4 D3 D2 D1 D0 SD_CLR 1 0 0 0 0 0 0 0 X X X X X X X X SD_H_WREG 1 0 0 1 0 0 0 0 X X X X X X X X SD_H_ZERO 1 0 0 1 0 0 0 1 X X X X X X X X SD_H_MID 1 0 0 1 0 0 1 0 X X X X X X X X SD_H_FULL 1 0 0 1 0 0 1 1 X X X X X X X X SD_L_WREG 1 0 0 0 1 0 0 0 X X X X X X X X SD_L_ZERO 1 0 0 0 1 0 0 1 X X X X X X X X SD_L_MID 1 0 0 0 1 0 1 0 X X X X X X X X SD_L_FULL 1 0 0 0 1 0 1 1 X X X X X X X X SD_W 1 0 0 0 0 1 X X X X X X X X X X QP_OFF 1 0 1 0 0 0 0 0 X X X X X X X X QP_ON 1 0 1 0 0 0 0 1 X X X X X X X X RST 1 1 0 0 0 0 0 0 X X X X X X X X WIPER Command The data byte writes to the wiper register and the potentiometer moves to the appropriate position. D[7:0] indicates the position of the wiper. D[7:0] = 0x00 moves the wiper to the position closest to L. D[7:0] = 0xFF moves the wiper closest to H. D[7:0] = 0x80 following power-on. SD_CLR Command Removes any existing shutdown condition. Connects all potentiometer terminals and returns the wiper to the value stored in the wiper register. The command does not affect the current status of the charge pump. SD_H_WREG Command Opens the H terminal and maintains the wiper at the wiper register location. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will close the H terminal and allow the wiper register to be written. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_H_ZERO Command Moves wiper to zero-scale position (0x00) and opens the H terminal. The wiper register remains unaltered. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register Maxim Integrated and close the H terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_H_MID Command Moves wiper to midscale position (0x80) and opens the H terminal. The wiper register remains unaltered. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register and close the H terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_H_FULL Command Moves wiper to full-scale position (0xFF) and opens H terminal. The wiper register remains unaltered. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register and close the H terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_L_WREG Command Opens the L terminal and maintains the wiper at the wiper register location. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will close the L terminal and allow wiper 12 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer register to be written. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_L_ZERO Command Moves wiper to zero-scale position (0x00) and opens the L terminal. The wiper register remains unaltered. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register and close the L terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_L_MID Command Moves wiper to midscale position (0x80) and opens the L terminal. The wiper register remains unaltered. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register and close the L terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. SD_W Command Opens the W terminal keeping the internal tap position the same as the wiper register. Writes cannot be made to the wiper registers while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register and close W terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. QP_ON Command Enables the onboard charge pump to allow low-supply voltage operation. This is the power-on default condition. Low supply voltage is 1.7V. QP_OFF Command Disables the on-board charge pump and places device in low power mode. Low supply voltage is limited to 2.6V. RST Command Returns device to power-on default conditions. Resets the wiper register to midscale (0x80), enables charge pump, and deasserts any shutdown modes. SD_L_FULL Command Moves wiper to full-scale position (0xFF) and opens the L terminal. The wiper register remains unaltered. Writes cannot be made to the wiper register while shutdown mode is engaged. Clearing shutdown mode will return the wiper to the position contained in the wiper register and close the L terminal. A RST will also deassert shutdown mode and return the wiper to midscale (0x80). This command does not affect the charge-pump status. Maxim Integrated 13 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Ordering Information PIN-PACKAGE INTERFACE TAPS END-TO-END RESISTANCE (kI) MAX5394LATA+T 8 TDFN-EP* SPI 256 10 MAX5394MATA+T 8 TDFN-EP* SPI 256 50 MAX5394NATA+T 8 TDFN-EP* SPI 256 100 PART Note: All devices operate over the -40°C to +125°C temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Chip Information PROCESS: BiCMOS Maxim Integrated 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 PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 8 TDFN-EP T822+2 21-0168 90-0065 14 MAX5394 Single, 256-Tap Volatile, SPI, Low-Voltage Linear Taper Digital Potentiometer Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 7/12 Initial release — 1 9/12 Revised the Absolute Maximum Ratings 2 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 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 © 2012 Maxim Integrated Products, Inc. 15 The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.