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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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Dual, 128-Tap, Low Voltage Digitally Controlled

Potentiometer (XDCP™)

ISL23428

The ISL23428 is a volatile, low voltage, low noise, low power,

128-tap, dual digitally controlled potentiometer (DCP) with an

SPI Bus™ interface. It integrates two DCP cores, wiper switches

and control logic on a monolithic CMOS integrated circuit.

Each digitally controlled potentiometer is implemented with a

combination of resistor elements and CMOS switches. The

position of the wipers are controlled by the user through the

SPI bus interface. Each potentiometer has an associated

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

position of the wiper. When powered on, the wiper of each DCP

will always commence at mid-scale (64 tap position).

The low voltage, low power consumption, and small package

of the ISL23428 make it an ideal choice for use in battery

pin allowing down to 1.2V bus operation, independent from the

directly to the ISL23428 without passing through a voltage

level shifter.

The DCP can be used as a three-terminal potentiometer or as a

two-terminal variable resistor in a wide variety of applications

including control, parameter adjustments, and signal processing.

Applications

• Power supply margining

• Trimming sensor circuits

• Gain adjustment in battery powered instruments

• RF power amplifier bias compensation

Features

• Two potentiometers per package

•128 resistor taps

•10k

 50kor 100k total resistance

• SPI serial interface

- No additional level translator for low bus supply

- Daisy Chaining of multiple DCPs

•Power supply

• Maximum supply current without serial bus activity

(standby)

•Shutdown Mode

- Forces the DCP into an end-to-end open circuit and RWi is

connected to RLi internally

- Reduces power consumption by disconnecting the DCP

resistor from the circuit

• Wiper resistance: 70

• Power-on preset to mid-scale (64 tap position)

• 14 Ld TSSOP or 16 Ld UTQFN packages

• Pb-free (RoHS compliant)

FIGURE 1. FORWARD AND BACKWARD RESISTANCE vs TAP

POSITION, 10kΩ DCP

0

2000

4000

6000

8000

10000

032

64

96

128

TAP POSITION (DECIMAL)

ISL28114

ISL23428

+

-

RL

RW

RH

August 25, 2011

FN7904.0