REV. 0

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© Analog Devices, Inc., 2001

Nonvolatile Memory,

1024-Position Digital Potentiometers

FUNCTIONAL BLOCK DIAGRAM

RDAC

REGISTER

EEMEM1

DIGITAL

REGISTER

EEMEM

CONTROL

28 BYTES

USER EEMEM

EEMEM2

AD5231

RDAC

DIGITAL

OUTPUT

BUFFER

CS

CLK

WP

PR

SDI

GND

SDO

RDY

SDO

SERIAL

INTERFACE

ADDR

DECODE

A

W

B

O1

O2

SDI

2

CODE – Decimal

100

75

0

0

1023

256

512

768

50

25

FEATURES

1024-Position Resolution

Full Monotonic Operation

10 k , 50 k , and 100 k

Terminal Resistance

Permanent Memory Write-Protection

Wiper Settings Read Back

Linear Increment/Decrement

Log Taper Increment/Decrement

Push Button Increment/Decrement Compatible

SPI Compatible Serial Interface with Readback Function

3 V to 5 V Single Supply or

2.5 V Dual Supply

28 Bytes User Nonvolatile Memory for Constant Storage

APPLICATIONS

Mechanical Potentiometer Replacement

Instrumentation: Gain, Offset Adjustment

Programmable Voltage to Current Conversion

Programmable Filters, Delays, Time Constants

Line Impedance Matching

Power Supply Adjustment

Low Resolution DAC Replacement

GENERAL DESCRIPTION

The AD5231 provides nonvolatile memory digitally controlled

potentiometers

perform the same electronic adjustment function as a mechanical

potentiometer. The AD5231’s versatile programming via a stan-

dard 3-wire serial interface allows 16 modes of operation and

adjustment, including scratch pad programming, memory stor-

ing and retrieving, increment/decrement, log taper adjustment,

wiper setting read back, and extra user-defined EEMEM.

In the scratch pad programming mode, a specific setting can be

programmed directly to the RDAC

tance at terminals W-A and W-B. The RDAC register can also

be loaded with a value previously stored in the EEMEM

ter. The value in the EEMEM can be changed or protected.

When changes are made to the RDAC register, the value of the

new setting can be saved into the EEMEM. Thereafter, such value

will be transferred automatically to the RDAC register during

system power ON. It is enabled by the internal preset strobe.

EEMEM can also be retrieved through direct programming and

external preset pin control.

Other operations include linear step increment and decrement

commands such that the setting in the RDAC register can be

moved UP or DOWN, one step at a time. For logarithmic changes

in wiper setting, a left/right bit shift command adjusts the level

in

±6 dB steps.

The AD5231 is available in thin TSSOP-16 package. All parts

are guaranteed to operate over the extended industrial tempera-

ture range of –40

°C to +85°C.

NOTES

*Patent pending