CAT5128

© 2008 SCILLC. All rights reserved.

1

Doc. No. MD-2128 Rev. B

Characteristics subject to change without notice

32-Tap Digital Up/Down Control Potentiometer

FEATURES

32-position linear taper potentiometer

Low power CMOS technology

Single supply operation: 2.5V – 5.5V

Discrete step-up/step-down digital control

Resistance values: 10kΩ, 50kΩ and 100kΩ

Available in SOT-23 8-lead Pb-free package

APPLICATIONS

Automated product calibration

Remote control adjustments

Offset, gain and zero control

Tamper-proof calibrations

Contrast, brightness and volume controls

Motor controls and feedback systems

Programmable analog functions

For Ordering Information details, see page 7.

DESCRIPTION

The CAT5128 is a single digitally programmable

potentiometer (DPP™) designed as an electronic

replacement for mechanical potentiometers and trim

pots. Ideal for automated adjustments on high volume

production lines, they are also well suited for

applications where equipment requiring periodic

adjustment is either difficult to access or located in a

hazardous or remote environment.

The CAT5128 contains a 32-tap series resistor array

connected between two terminals A and B. An

up/down counter and decoder that are controlled by

two input pins, determines which tap is connected to

the wiper, W. Wiper-control of the CAT5128 is

accomplished with two input control pins, UP

¯¯ and

DOWN

¯¯¯¯¯¯. A high-to-low transition on the UP

¯¯ input

increments the wiper position and a high-to-low

transition on the DOWN

¯¯¯¯¯¯ input decrements the wiper

position. The tap position is not stored in memory.

The wiper is always set to the mid point, tap 15 at

power up.

The digitally programmable potentiometer can be used

as a three-terminal resistive divider or as a two-terminal

variable resistor. DPPs bring variability and program-

mability to a wide variety of applications including

control, parameter adjustments, and signal processing.

FUNCTIONAL DIAGRAM

A

B

UP/DOWN

Control

Power On Recall

UP

DOWN

A

B

GND

W

W

UP

DOWN

Electronic Potentiometer

Implementation

Detailed

General

ONE

OF

THIRTY TWO

DECODER

31

30

29

28

2

1

0

TRANSFER

GATES

RESISTOR

ARRAY

CONTROL

CIRCUITRY

5-BIT

UP/DOWN

COUNTER

GND

A

W

B