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Wolfson Microelectronics

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© 1996 Wolfson Microelectronics

Production Data

Jan. 1997 Rev. 1.0

Low-power Quadruple 8-Bit DAC

Description

WM5621L is a quadruple 8-bit digital to analogue converter

(DAC) with buffered reference inputs (high impedance). The

DAC produces an output voltage that ranges between

either one or two times the reference voltage and GND. The

DAC is monotonic. The device operates from a single

supply in the range 2.7V to 5.5V. A power-on reset function

is incorporated to provide repeatable start-up conditions. A

global hardware shut-down terminal and the capacity to

shut-down each individual DAC with software are provided

to minimize power consumption.

WM5621L interfaces to all popular microcontrollers and

microprocessors via a three wire serial interface with CMOS

compatible, schmitt trigger, digital inputs. Alternatively a two

wire serial interface can be activated. An 11-bit command

word consists of eight bits of data, two DAC select bits and

a range bit for selection between the times one or times two

output range. The DACregisters are double buffered which

allows a complete set of new values to be written to the

device, and then under control of HWACT, all of the DAC

outputs are simultaneously updated.

Ideal in space critical applications WM5621L is available

in small outline and DIP packages and is characterized for

operation from -25

Features

•

Individual (or all) DAC's can be powered-down

•

One low-power 8-bit voltage output DAC

•

Three 8-bit voltage output DACs

•

Fast serial interface (1 MHz max)

•

Simple 2 or 3 wire interface

•

Programmable for 1 or 2 times output range

•

High impedance reference inputs for each DAC

•

Simultaneous update facility

•

Extended temperature range (-25

•

Single supply operation, range 2.7 V to 5.5 V

•

•

•

Low power specification:

All DACs on

: 3.6 mW at 3.6 V typ

: 6 mW at 5 V typ

Low power DAC

: 0.54 mW at 3.6V typ

All DAC's shutdown

: 0.18 mW at 3.6V typ

•

Guaranteed monotonic output

Applications

•

Mobile Communications

•

Programmable d.c. voltage sources

•

Digitally controlled attenuator/amplifier

•

Signal synthesis

•

Automatic test equipment

Block Diagram

WM5621L