DATASHEET ISL23425 FN7873 Rev 1.00 Dual, 256-Tap, Low Voltage Digitally Controlled Potentiometer (XDCP) September 11, 2015 The ISL23425 is a volatile, low voltage, low noise, low power, Features 256-tap, dual digitally controlled potentiometer (DCP) with an Two potentiometers per package SPI Bus interface. It integrates two DCP cores, wiper switches and control logic on a monolithic CMOS integrated circuit. 256 resistor taps Each digitally controlled potentiometer is implemented with a 10k 50k or 100k total resistance combination of resistor elements and CMOS switches. The SPI serial interface position of the wipers are controlled by the user through the - No additional level translator for low bus supply SPI bus interface. Each potentiometer has an associated - Daisy Chaining of multiple DCPs volatile Wiper Register (WRi, i = 0, 1) that can be directly written to and read by the user. The contents of the WRi controls the Maximum supply current without serial bus activity position of the wiper. When powered on, the wiper of each DCP (standby) will always commence at mid-scale (128 tap position). - 4A V and V = 5V CC LOGIC The low voltage, low power consumption, and small package - 1.7A V and V = 1.7V CC LOGIC of the ISL23425 make it an ideal choice for use in battery Shutdown Mode operated equipment. In addition, the ISL23425 has a V LOGIC - Forces the DCP into an end-to-end open circuit and RWi is pin allowing down to 1.2V bus operation, independent from the connected to RLi internally V value. This allows for low logic levels to be connected CC directly to the ISL23425 without passing through a voltage - Reduces power consumption by disconnecting the DCP level shifter. resistor from the circuit The DCP can be used as a three-terminal potentiometer or as a Power supply two-terminal variable resistor in a wide variety of applications -V = 1.7V to 5.5V analog power supply CC including control, parameter adjustments, and signal processing. -V = 1.2V to 5.5V SPI bus/logic power supply LOGIC Wiper resistance: 70 typical V = 3.3V Applications CC Power-on preset to mid-scale (128 tap position) Power supply margining Extended industrial temperature range: -40C to +125C Trimming sensor circuits 14 Ld TSSOP or 16 Ld TQFN packages Gain adjustment in battery powered instruments Pb-free (RoHS compliant) RF power amplifier bias compensation 10000 V REF 8000 RH1 6000 - V REF M 1 DCP RW1 4000 OF + ISL23325 ISL28114 2000 RL1 0 0 64 128 192 256 TAP POSITION (DECIMAL) FIGURE 1. FORWARD AND BACKWARD RESISTANCE vs TAP FIGURE 2. V ADJUSTMENT REF POSITION, 10k DCP FN7873 Rev 1.00 Page 1 of 20 September 11, 2015 RESISTANCE ()ISL23425 Block Diagram V V RH0 RH1 LOGIC CC SCK POWER UP SDI INTERFACE, SPI CONTROL WR0 SDO WR1 INTERFACE AND VOLATILE VOLATILE STATUS CS REGISTER REGISTER LOGIC AND AND WIPER WIPER CONTROL CONTROL CIRCUITRY CIRCUITRY RW0 RL0 RW1 RL1 GND Pin Configurations Pin Descriptions TSSOP TQFN SYMBOL DESCRIPTION ISL23425 (14 LD TSSOP) 1, 7 5, 6, 15 GND Ground pin TOP VIEW 216 V SPI bus/logic supply LOGIC Range 1.2V to 5.5V GND 1 14 V CC 3 1 SDO Logic Pin - Serial bus data output V 2 13 RL0 LOGIC (configurable) SDO 3 12 RW0 4 2 SCK Logic Pin - Serial bus clock input SCK 4 11 RH0 5 3 SDI Logic Pin - Serial bus data input SDI 5 10 RH1 64 CS Logic Pin - Active low chip select CS 6 9 RW1 8 8 RL1 DCP1 low terminal GND 7 8 RL1 99RW1 DCP1 wiper terminal 10 10 RH1 DCP1 high terminal ISL23425 11 11 RH0 DCP0 high terminal (16 LD TQFN) 12 12 RW0 DCP0 wiper terminal TOP VIEW 13 13 RL0 DCP0 low terminal 14 14 V Analog power supply. CC Range 1.7V to 5.5V 1 12 7 NC Not Connected SDO RW0 SCK 2 11 RH0 SDI 3 10 RH1 CS 4 9 RW1 FN7873 Rev 1.00 Page 2 of 20 September 11, 2015 GND 5 16 V LOGIC GND 6 15 GND NC 7 14 V CC RL1 8 13 RL0