FUNCTIONAL BLOCK DIAGRAM
BURIED ZENER REF
COMP-
ARATOR
ANALOG
IN
DB7
V
CC
V
SS
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 ms 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
2
L (integrated injection logic). Laser trim-
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.