WM2639

12-Bit Parallel Input Voltage Output DAC

with Internal Reference

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 contain final specifications

current on publication date. Supply of products

conforms to Wolfson Microelectronics’ Terms

and conditions..

Master 15/07/99 15:02

©1999 Wolfson Microelectronics Ltd

.

FEATURES

•

12-bit voltage output DAC

•

Single supply 2.7V to 5.5V operation

•

DNL

±±0.3 LSBs, INL ±±1.2 LSBs

•

Internal programmable voltage reference

•

Settling time 1

µµs typical

•

12-bit microprocessor compatible interface

•

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

•

Mass storage devices

ORDERING INFORMATION

DEVICE

TEMP. RANGE

PACKAGE

WM2639CDT

0

° to 70°C

20-pin TSSOP

WM2639IDT

-40

° to 85°C

20-pin TSSOP

DESCRIPTION

The WM2639 is a 12-bit voltage output, resistor string, digital-to-

analogue converter. A hardware controlled power down mode is

provided that reduces current consumption to 10nA. The device

has been designed to interface efficiently to industry standard

microprocessors and DSPs.

The WM2639 features an internal programmable voltage reference

simplifying overall system design. The reference voltage can also

be supplied externally.

Excellent performance is delivered with a typical DNL of 0.3 LSBs

and typical INL of 1.2 LSBs. The output stage is buffered by a x2

gain near rail-to-rail amplifier, which features a Class A output

stage (slow mode, Class AB). The 12 data bits are double buffered

enabling the output to be asynchronously updated under hardware

control. The settling time of the DAC is software programmable to

allow the designer to optimise speed versus power dissipation.

The device is available in a 20-pin TSSOP package. Commercial

temperature (0° to 70°C) and Industrial temperature (-40° to 85°C)

variants are supported.

BLOCK DIAGRAM

TYPICAL PERFORMANCE

(13) OUT

data

REF(12)

POWER-ON

RESET

D[0-11]

(19,20, 1-10)

NWE (17)

(14)

GND

POWERDOWN

CONTROL

REFERENCE

INPUT

BUFFER

WM2639

X1

X2

DAC

OUTPUT

BUFFER

NCS (18)

12-BIT

DAC

LATCH

12-BIT

INPUT

REGISTER

2-BIT

REFERENCE

SELECT

LATCH

1.024V/2.048V

SELECTABLE

REFERENCE

X1

REFERENCE

OUTPUT BUFFER

WITH OUPUT

ENABLE

VDD

(11)

(16)

NLDAC

2-BIT

CONTROL

LATCH

REG (15)

5V = VDD, V

REF

-1

-0.8

-0.4

-0.2

0.2

0.4

0.8

1

512

1024

2048

2559

3583

4095