FUNCTIONAL BLOCK DIAGRAM

BURIED ZENER REF

COMP-

ARATOR

ANALOG

IN

DB7

DIGITAL

COMMON

CONVERT

INT

CLOCK

8-BIT

SAR

DB6

DB5

DB4

DB3

DB2

DB1

DB0

MSB

LSB

ANALOG

COMMON

BIPOLAR

OFFSET

CONTROL

DATA

READY

AD673

5k

DATA

ENABLE

8-BIT

CURRENT

OUTPUT

DAC

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

8-Bit A/D Converter

AD673*

FEATURES

Complete 8-Bit A/D Converter with Reference, Clock

and Comparator

30

s Maximum Conversion Time

Full 8- or 16-Bit Microprocessor Bus Interface

Unipolar and Bipolar Inputs

No Missing Codes Over Temperature

Operates on +5 V and –12 V to –15 V Supplies

MIL-STD-883 Compliant Version Available

GENERAL DESCRIPTION

The AD673 is a complete 8-bit successive approximation

analog-to-digital converter consisting of a DAC, voltage refer-

ence, clock, comparator, successive approximation register

(SAR) and 3-state output buffers—all fabricated on a single

chip. No external components are required to perform a full ac-

curacy 8-bit conversion in 20

µs.

The AD673 incorporates advanced integrated circuit design and

processing technologies. The successive approximation function

is implemented with I

ming of the high stability SiCr thin-film resistor ladder network

insures high accuracy, which is maintained with a temperature

compensated sub-surface Zener reference.

Operating on supplies of +5 V and –12 V to –15 V, the AD673

will accept analog inputs of 0 V to +10 V or –5 V to +5 V. The

trailing edge of a positive pulse on the CONVERT line initiates

the 20

µs conversion cycle. DATA READY indicates comple-

tion of the conversion.

The AD673 is available in two versions. The AD673J as speci-

fied over the 0

°C to +70°C temperature range and the AD673S

guarantees

±1/2 LSB relative accuracy and no missing codes

from –55

°C to +125°C.

Two package configurations are offered. All versions are also of-

fered in a 20-pin hermetically sealed ceramic DIP. The AD673J

is also available in a 20-pin plastic DIP.

*Protected by U.S. Patent Nos. 3,940,760; 4,213,806; 4,136,349; 4,400,689;

and 4,400,690.

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

Tel: 617/329-4700

Fax: 617/326-8703

PRODUCT HIGHLIGHTS

1. The AD673 is a complete 8-bit A/D converter. No external

components are required to perform a conversion.

2. The AD673 interfaces to many popular microprocessors

without external buffers or peripheral interface adapters.

3. The device offers true 8-bit accuracy and exhibits no missing

codes over its entire operating temperature range.

4. The AD673 adapts to either unipolar (0 V to +10 V) or

bipolar (–5 V to +5 V) analog inputs by simply grounding or

opening a single pin.

5. Performance is guaranteed with +5 V and –12 V or –15 V

supplies.

6. The AD673 is available in a version compliant with MIL-

STD-883. Refer to the Analog Devices Military Products

Databook or current AD673/883B data sheet for detailed

specifications.