WM2637

Dual 10-Bit Serial Input Voltage Output DAC

with Internal Reference

Production Data, Rev 1.0, July 1999

WOLFSON MICROELECTRONICS LTD

Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK

Tel: +44 (0) 131 667 9386

Fax: +44 (0) 131 667 5176

Email: sales@wolfson.co.uk

http://www.wolfson.co.uk

Production Data contains final specifications

current on publication date. Supply of products

conforms to Wolfson Microelectronics' Terms

and Conditions.

Last printed 15/07/99 15:56

©1999 Wolfson Microelectronics Ltd

.

FEATURES

•

Dual 10-bit voltage output DAC

•

Single 2.7V to 5.5V supply

•

DNL

±±0.1 LSBs, INL ±±0.4 LSBs

•

Internal programmable voltage reference

•

Low power consumption:

• 5.5 mW, slow mode - 5V supply

• 3.3 mW, slow mode - 3V supply

•

TMS320, (Q) SPI

interface

•

Programmable settling time of 1

µµs or 3.5µµs typical

•

Power down mode 10nA

APPLICATIONS

•

Battery powered test instruments

•

Digital offset and gain adjustment

•

Battery operated/remote industrial controls

•

Machine and motion control devices

•

Wireless telephone and communication systems

•

Speech synthesis

•

Arbitrary waveform generation

ORDERING INFORMATION

DEVICE

TEMP. RANGE

PACKAGE

WM2637CD

0° to 70°C

8-pin SOIC

WM2637ID

-40° to 85°C

8-pin SOIC

DESCRIPTION

The WM2637 is a dual 10-bit voltage output, resistor string, digital-

to-analogue converter. A software controlled power down mode is

provided that reduces current consumption to 10nA.

The WM2637 features an internal programmable voltage reference

simplifying overall system design. A reference voltage may also be

supplied externally.

The device has been designed to interface efficiently to industry

standard microprocessors and DSPs, including the TMS320

family. The WM2637 is programmed with a 16-bit serial word

comprising of a latch address, mode DAC control bits and DAC or

control data.

Excellent performance is delivered with a typical DNL of 0.1 LSBs.

The programmable settling time allows the designer to optimize

speed versus power consumption. The output stage is buffered by

a x2 gain near rail-to-rail amplifier.

The device is available in an 8-pin SOIC package ideal for space-

critical applications. Commercial temperature (0

° to 70°C) and

industrial temperature (-40

° to 85 °C) variants are supported.

BLOCK DIAGRAM

TYPICAL PERFORMANCE

(7) OUTB

(4) OUTA

10-BIT

DAC B

HOLDING

LATCH

10-BIT

DAC A

LATCH

REF(6)

POWER-ON

RESET

DIN (1)

SCLK (2)

NCS (3)

(5)

AGND

POWERDOWN/

SPEED

CONTROL

10-BIT

DAC B

LATCH

DAC

OUTPUT

BUFFER

2-BIT

CONTROL

LATCH

X1

X2

X2

DAC

OUTPUT

BUFFER

REFERENCE

INPUT

BUFFER

REFERENCE

INPUT BUFFER

16-BIT

SHIFT

REGISTER

AND

CONTROL

LOGIC

2-BIT

REFERENCE

SELECT

LATCH

1.024V/2.048V

SELECTABLE

REFERENCE

X1

VDD

(8)

c

X1

REFERENCE

OUTPUT BUFFER

WITH OUPUT

ENABLE

WM2637

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0

256

512

767

1023

DIGITAL CODE

5V = VDD, V