8

FN8177.5

April 18, 2007

Applications Information

Electronic digitally controlled potentiometers (XDCP) provide

three powerful application advantages; (1) the variability and

reliability of a solid-state potentiometer, (2) the flexibility of

computer-based digital controls, and (3) the retentivity of

nonvolatile memory used for the storage of multiple

potentiometer settings or data.

Basic Configurations of Electronic Potentiometers

Basic Circuits

I

THREE-TERMINAL POTENTIOMETER;

VARIABLE VOLTAGE DIVIDER

TWO-TERMINAL VARIABLE RESISTOR;

VARIABLE CURRENT

CASCADING TECHNIQUES

BUFFERED REFERENCE VOLTAGE

–

+

+5V

+V

-5V

VW

OP-07

VW/RW

+V

+V

+V

X

(a)

(b)

NONINVERTING AMPLIFIER

+

–

LM308A

VOLTAGE REGULATOR

317

OFFSET VOLTAGE ADJUSTMENT

+

–

100k

Ω

10k

Ω

10k

Ω

10k

Ω

-12V

+12V

TL072

COMPARATOR WITH HYSTERESIS

+

–

LT311A

+5V

-5V

(FOR ADDITIONAL CIRCUITS SEE AN115)

X9313