CAT5251

© Catalyst Semiconductor, Inc.

1

Doc. No. MD-2017 Rev. F

Characteristics subject to change without notice

Quad Digitally Programmable Potentiometer (DPP™) with

256 Taps and SPI Interface

FEATURES

Four linear-taper digitally programmable

potentiometers

254 resistor taps per potentiometer

End to end resistance 50kΩ or 100kΩ

Potentiometer control and memory access via

SPI interface

Low wiper resistance, typically 100Ω

Nonvolatile memory storage for up to four

wiper settings for each potentiometer

Automatic recall of saved wiper settings at

power up

2.5 to 6.0 volt operation

Standby current less than 1µA

1,000,000 nonvolatile WRITE cycles

100 year nonvolatile memory data retention

SOIC 24-lead and TSSOP 24-lead

Industrial temperature range

For Ordering Information details, see page 14.

PIN CONFIGURATION

SOIC 24-Lead (W)

TSSOP 24-Lead (Y)

SO

1

24 HOLD

¯¯¯¯¯

A0

2

23 SCK

3

4

5

NC

6

19 NC

7

18 GND

8

9

CS

¯¯¯ 11

14 A1

WP

¯¯¯ 12

13 SI

CAT

5251

DESCRIPTION

The

CAT5251

is

four

Digitally

Programmable

Potentiometers (DPPs™) integrated with control logic

and 16 bytes of NVRAM memory. Each DPP consists

of a series of resistive elements connected between

two externally accessible end points. The tap points

between each resistive element are connected to the

wiper outputs with CMOS switches. A separate 8-bit

control register (WCR) independently controls the

wiper tap switches for each DPP. Associated with

each wiper control register are four 8-bit non-volatile

memory data registers (DR) used for storing up to four

wiper settings. Writing to the wiper control register or

any of the non-volatile data registers is via a SPI serial

bus. On power-up, the contents of the first data

register (DR0) for each of the four potentiometers is

automatically loaded into its respective wiper control

register.

The CAT5251 can be used as a potentiometer or as a

two terminal, variable resistor. It is intended for circuit

level or system level adjustments in a wide variety of

applications. It is available in the -40°C to 85°C

industrial operating temperature range and offered in

a 24-lead SOIC and TSSOP package.

FUNCTIONAL DIAGRAM

A0

A1

WP

HOLD

NONVOLATILE

DATA

REGISTERS

WIPER

CONTROL

REGISTERS

CONTROL

LOGIC

SPI BUS

INTERFACE

SCK

SI

CS

SO