DATASHEET ISL23418 FN7901 Rev 1.00 Single, 128-Tap, Low Voltage Digitally Controlled Potentiometer (XDCP) September 24, 2015 The ISL23418 is a volatile, low voltage, low noise, low power, Features SPI bus, 128 taps, single digitally controlled potentiometer 128 Resistor Taps (DCP), which integrates DCP core, wiper switches, and control logic on a monolithic CMOS integrated circuit. SPI Serial Interface - No Additional Level Translator for Low Bus Supply The digitally controlled potentiometer is implemented with a - Daisy Chaining of Multiple DCP combination of resistor elements and CMOS switches. The position of the wiper is controlled by the user through the SPI Wiper Resistance: 70 Typical V = 3.3V CC bus interface. The potentiometer has an associated volatile Shutdown Mode: Forces DCP into End-to-end Open Circuit Wiper Register (WR) that can be directly written to and read by RW Shorted to RL Internally the user. The contents of the WR controls the position of the wiper. When powered on, the ISL23418 wiper always Power-on Preset to Mid-scale (64-tap Position) commences at mid-scale (64-tap position). Shutdown and Standby Current <2.8A Max The low voltage, low power consumption, and small package Power Supply size of the ISL23418 make it an ideal choice for use in battery -V = 1.7V to 5.5V Analog Power Supply CC operated equipment. The ISL23418 has a V pin allowing LOGIC -V = 1.2V to 5.5V SPI Bus/Logic Power Supply LOGIC down to 1.2V bus operation, independent from the V value. CC This allows for low logic levels to be connected directly to the DCP Terminal Voltage from 0V to V CC ISL23418 without passing through a voltage level shifter. 10k 50k or 100k Total Resistance The DCP can be used as a three-terminal potentiometer or as a Extended Industrial Temperature Range: -40C to +125C two-terminal variable resistor in a wide variety of applications 10 Ld MSOP or 10 Ld TQFN Packages including control, parameter adjustments, and signal processing. Pb-free (RoHS compliant) Related Literature Applications See ISL23415, Single, Low Voltage Digitally Controlled Power Supply Margining Potentiometer (XDCP) RF Power Amplifier Bias Compensation LCD Bias Compensation Gain Adjustment in Battery Powered Instruments Portable Medical Equipment Calibration 10000 V REF 8000 6000 RH1 - VREF M 4000 RW1 ISL23418 + ISL28114 2000 RL1 0 0 25 50 75 100 125 TAP POSITION (DECIMAL) FIGURE 1. FORWARD AND BACKWARD RESISTANCE vs TAP FIGURE 2. V ADJUSTMENT REF POSITION, 10k FN7901 Rev 1.00 Page 1 of 20 September 24, 2015 RESISTANCE ()ISL23418 Block Diagram V V CC LOGIC RH SCK POWER-UP INTERFACE, SDI I/O BLOCK LEVEL CONTROL WR SDO SHIFTER AND VOLATILE STATUS CS REGISTER LOGIC AND WIPER CONTROL CIRCUITRY RL RW GND Pin Configurations Pin Description ISL23418 (10 LD MSOP) MSOP TQFN SYMBOL DESCRIPTION TOP VIEW 110 V SPI bus/logic supply range 1.2V to LOGIC O 10 GND V 1 LOGIC 5.5V SCK 2 V 9 CC 2 1 SCK Logic pin: serial bus clock input RH SDO 3 8 3 2 SDO Logic pin: serial bus data output 7 SDI 4 RW (configurable) CS RL 5 6 4 3 SDI Logic pin: serial bus data input 54 CS Logic pin: active low Chip Select ISL23418 65 RL DCP low terminal (10 LD TQFN) TOP VIEW 76 RW DCP wiper terminal 8 7 RH DCP high terminal 98 V Analog power supply range 1.7V to CC O 5.5V SCK 1 9 GND 10 9 GND Ground pin SDO 2 8 V CC SDI 3 7 RH CS 4 6 RW FN7901 Rev 1.00 Page 2 of 20 September 24, 2015 RL 5 10 V LOGIC