X9319

6 of 10

REV 1.7 7/10/03

www.xicor.com

PIN DESCRIPTIONS

equivalent to the fixed terminals of a mechanical

ences the relative position of the terminal in relation to

wiper movement direction selected by the U/D input

and not the voltage potential on the terminal.

R

W

able terminal of a mechanical potentiometer. The posi-

tion of the wiper within the array is determined by the

control inputs. The wiper terminal series resistance is

typically 40

Ω.

Up/Down (U/D)

The U/D input controls the direction of the wiper move-

ment and whether the counter is incremented or decre-

mented.

Increment (INC)

The INC input is negative-edge triggered. Toggling INC

will move the wiper and either increment or decrement

the counter in the direction indicated by the logic level

on the U/D input.

Chip Select (CS)

The device is selected when the CS input is LOW. The

current counter value is stored in nonvolatile memory

when CS is returned HIGH while the INC input is also

HIGH. After the store operation is complete the X9319

will be placed in the low power standby mode until the

device is selected once again.

PIN CONFIGURATION

PIN NAMES

PRINCIPLES OF OPERATION

There are three sections of the X9319: the control

section, the nonvolatile memory, and the resistor array.

The control section operates just like an up/down

counter. The output of this counter is decoded to turn

on a single electronic switch connecting a point on the

resistor array to the wiper output. The contents of the

counter can be stored in nonvolatile memory and

retained for future use. The resistor array is comprised

of

99

individual

resistors

connected

in

series.

Electronic switches at either end of the array and

between each resistor provide an electrical connection

The wiper acts like its mechanical equivalent and does

not move beyond the first or last position. That is, the

counter does not wrap around when clocked to either

extreme.

The electronic switches on the device operate in a

“make before break” mode when the wiper changes

tap positions. If the wiper is moved several positions,

porarily be reduced by a significant amount if the wiper

is moved several positions.

When the device is powered-down, the last wiper posi-

tion stored will be maintained in the nonvolatile mem-

ory. When power is restored, the contents of the

memory are recalled and the wiper is set to the value

last stored.

INC

U/D

1

2

3

4

8

7

6

5

X9319

DIP/SOIC

CS

Symbol

Description

High terminal

Wiper terminal

Low terminal

Ground

Supply voltage

U/D

Up/Down control input

INC

Increment control input

CS

Chip select control input