1

Doc. No. 2003, Rev. F

© 2004 by Catalyst Semiconductor, Inc.

Characteristics subject to change without notice

1

2

3

4

5

6

7

14

13

12

11

8

10

9

VDD

CLK

RDY/BSY

CS

DI

DO

PROG

VREFH

NC

VOUT

NC

NC

VREFL

GND

1

2

3

4

5

6

7

14

13

12

11

8

10

9

VDD

CLK

RDY/BSY

CS

DI

DO

PROG

VREFH

NC

VOUT

NC

NC

VREFL

GND

CAT521

Configured Digitally Programmable Potentiometer (DPP™):

Programmable Voltage Applications

FEATURES

voltage source in DAC-like applications

APPLICATIONS

self-calibrating and adaptive control systems

DESCRIPTION

The CAT521 is a 8-bit digitally-programmable

potentiometer (DPP™) configured for programmable

voltage and DAC-like applications. Intended for final

calibration of products such as camcorders, fax

machines and cellular telephones on automated high

volume production lines, it is also well suited for

self-calibrating systems and for applications where

equipment which requires periodic adjustment is either

difficult to access or in a hazardous environment.

The programmable DPP has an output voltage range

which includes both supply rails. The wiper is buffered

by a rail to rail op amp. The wiper setting, stored in

non-volatile NVRAM memory, is not lost when the

device is powered down and is automatically reinstated

when power is returned. The wiper can be dithered to

test new output values without effecting the stored

FUNCTIONAL DIAGRAM

PIN CONFIGURATION

settings and stored settings can be read back without

disturbing the DPP’s output.

The CAT521 is controlled with a simple 3-wire, Microwire-

like serial interface. A Chip Select pin allows several

devices to share a common serial interface.

Communication back to the host controller is via a single

serial data line thanks to the CAT521 Tri-Stated Data

Output pin. A RDY/

BSY output working in concert with

an internal low voltage detector signals proper operation

of the non-volatile NVRAM memory Erase/Write cycle.

The CAT521 is available in 0

°C to 70°C commercial and

-40

°C to 85°C industrial operating temperature ranges.

Both 14-pin plastic DIP and surface mount packages

are available.

DIP Package (P, L)

SOIC Package (J, W)

CAT521

CAT521

CAT521

ALO

GEN FR

TM

LEAD FREE

RDY/BSY

PROG

PROGRAM

CONTROL

DI

CS

CLK

SERIAL

DATA

OUTPUT

REGISTER

GND

V

DD

14

7

5

2

4

12

OUT

V

6

DO

8

9

31

+

SERIAL

CONTROL

NVRAM

WIPER

CONTROL

REGISTER

AND

V

REFH

VREFL