CAT5116

6

Doc. No. 2118, Rev. J

AC Timing

CS

INC

U

/D

RW

t

CI

t

CYC

t

IL

MI

(3)

90%

90%

10%

(store)

t

F

t

R

t

IW

tID

tDI

t

IH

t

CPH

t

IC

(2) This parameter is periodically sampled and not 100% tested.

(3) MI in the AC Timing diagram refers to the minimum incremental change in the W output due to a change in the wiper position.

DEVICE OPERATION

The CAT5116 operates like a digitally controlled

potentiometer's wiper. There are 100 tap positions

99 resistor elements connected in series between the

connected to one of the 100 taps and is controlled by

three inputs,

INC, U/D and CS. These inputs control a

seven-bit up/down counter whose output is decoded to

select the wiper position. The selected wiper position

can be stored in nonvolatile memory using the

INC and

CS inputs.

With

CS set LOW the CAT5116 is selected and will

respond to the U/

D and INC inputs. HIGH to LOW

transitions on

INC wil increment or decrement the

wiper (depending on the state of the U/

D input and

seven-bit counter). The wiper, when at either fixed

terminal, acts like its mechanical equivalent and does

not move beyond the last position. The value of the

counter is stored in nonvolatile memory whenever

CS

transitions HIGH while the

INC input is also HIGH. When

the CAT5116 is powered-down, the last stored wiper

counter position is maintained in the nonvolatile memory.

When power is restored, the contents of the memory are

recalled and the counter is set to the value stored.

With

INC set low, the CAT5116 may be de-selected

and powered down without storing the current wiper

position in nonvolatile memory. This allows the

system to always power up to a preset value stored

in nonvolatile memory.

OPERATING MODES

Potentiometer

Equivalent Circuit

X: High or Low

INC

CS

U/D

Operation

High to Low

Low

High

Wiper Toward H

High to Low

Low

Low

Wiper Toward L

High

Low to High

X

Store Wiper Position

Low

Low to High

X

No Store, Return to Standby

X

High

X

Standby