5

FN8188.2

February 1, 2008

AC Timing

Power-up and Power-down Requirements

There are no restrictions on the power-up or power-down

Pin Descriptions

applied independently or at the same time.

fixed terminals of a mechanical potentiometer. The minimum

relation to wiper movement direction selected by the U/D

input per potentiometer.

potentiometer, which is equivalent to the movable terminal of

a mechanical potentiometer.

Up/Down (U/D)

The U/D input controls the direction of a single

potentiometer’s wiper movement and whether the counter is

incremented or decremented.

Increment (INC)

The INC input is negative-edge triggered. Toggling INC will

move the wiper and either increment or decrement the

pertaining potentiometer’s counter in the direction indicated

by the logic level on the pertaining potentiometer’s U/D

input.

Chip Select (CS)

A potentiometer is selected when the pertaining CS input is

LOW. Its current counter value is stored in nonvolatile memory

when the pertaining CS is returned HIGH while the pertaining

INC input is also HIGH. After the store operation is complete

the affected potentiometer will be placed in the low power

standby mode until the potentiometer is selected once again.

Principles of Operation

There are multiple sections for each potentiometer in the

X93256: an input control, a counter and decode section; the

nonvolatile memory; and a resistor array. Each input control

INC Inactive to CS Inactive

1

µs

CS Deselect Time (No store)

250

ns

CS Deselect Time (Store)

10

ms

INC Cycle Time

2

µs

(Note 5)

INC Input Rise and Fall time

500

µs

(Note 5)

VCC Power-up Rate

0.2

50

V/ms

Store Cycle

510

ms

SYMBOL

PARAMETER

MIN

(Note 7)

TYP

(Note 4)

MAX

(Note 7)

UNIT

CS

INC

U/D

10%

90%

90%

(STORE)

X93256