REV. A

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

Octal 8-Bit TrimDAC

with Power Shutdown

AD8801/AD8803

© Analog Devices, Inc., 1995

One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

FEATURES

Low Cost

Replaces Eight Potentiometers

Eight Individually Programmable Outputs

Three-Wire Serial Input

Power Shutdown

≤ 25 W Including I

Midscale Preset, AD8801

+3 V to +5 V Single Supply Operation

APPLICATIONS

Automatic Adjustment

Trimmer Potentiometer Replacement

Video and Audio Equipment Gain and Offset Adjustment

Portable and Battery Operated Equipment

GENERAL DESCRIPTION

The AD8801/AD8803 provides eight digitally controlled dc

voltage outputs. This potentiometer divider TrimDAC

replacement of the mechanical trimmer function in new designs.

The AD8801/AD8803 is ideal for dc voltage adjustment

applications.

Easily programmed by serial interfaced microcontroller ports,

the AD8801 with its midscale preset is ideal for potentiometer

replacement where adjustments start at a nominal value. Appli-

cations such as gain control of video amplifiers, voltage con-

trolled frequencies and bandwidths in video equipment,

geometric correction and automatic adjustment in CRT com-

puter graphic displays are a few of the many applications ideally

suited for these parts. The AD8803 provides independent con-

trol of both the top and bottom end of the potentiometer divider

allowing a separate zero-scale voltage setting determined by the

vices with a limited allowable voltage control range.

FUNCTIONAL BLOCK DIAGRAM

(DACs 2–7 Omitted for Clarity)

Internally the AD8801/AD8803 contain eight voltage output

digital-to-analog converters, sharing a common reference volt-

age input.

Each DAC has its own DAC register that holds its output state.

These DAC registers are updated from an internal serial-to-par-

allel shift register that is loaded from a standard three-wire serial

input digital interface. Eleven data bits make up the data word

clocked into the serial input register. This data word is decoded

where the first 3 bits determine the address of the DAC register

to be loaded with the last 8 bits of data. The AD8801/AD8803

consumes only 5

µA from 5 V power supplies. In addition, in

shutdown mode reference input current consumption is also re-

duced to 5

µA while saving the DAC latch settings for use after

return to normal operation.

The AD8801/AD8803 is available in 16-pin plastic DIP and the

1.5 mm height SO-16 surface mount packages.

TrimDAC is a registered trademark of Analog Devices, Inc.

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AD8801/AD8803

O1

O8

SHDN

RS

CS

CLK

SDI

GND

8

8

8

88

8

3

DAC

SELECT

11-BIT

SERIAL

LATCH

D

CK RS

1

8

ADDRESS

8-BIT

LATCH

CK

RS

8-BIT

LATCH

CK

RS

See the AD8802/AD8804 for a twelve channel version of this product.