Complete 8-Bit
A-to-D Converter
a
AD570*
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Complete A/D Converter with Reference and Clock
Fast Successive Approximation Conversion: 25 s
No Missing Codes Over Temperature
0؇C to +70؇C: AD570J
–55؇C to +125؇C: AD570S
Digital Multiplexing: Three-State Outputs
18-Pin Ceramic DIP
Low Cost Monolithic Construction
PRODUCT DESCRIPTION
The AD570 is an 8-bit successive approximation A/D converter
consisting of a DAC, voltage reference, clock, comparator, suc-
cessive approximation register and output buffers—all fabricated
on a single chip. No external components are required to per-
form a full accuracy 8-bit conversion in 25 µs.
The AD570 incorporates the most advanced integrated circuit
design and processing technology available today. I2L (inte-
grated injection logic) processing in the fabrication of the SAR
function along with laser trimming of the high stability SiCr
thin-film resistor ladder network at the wafer stage (LWT) and a
temperature compensated, subsurface Zener reference insures
full 8-bit accuracy at low cost.
PRODUCT HIGHLIGHTS
1. The AD570 is a complete 8-bit A/D converter. No external
components are required to perform a conversion. Full-scale
calibration accuracy of ±0.8% (2 LSB of 8 bits) is achieved
without external trims.
2. The AD570 is a single chip device employing the most ad-
vanced IC processing techniques. Thus, the user has at his
disposal a truly precision component with the reliability and
low cost inherent in monolithic construction,
Operating on supplies of +5 V and –15 V, the AD570 accepts
analog inputs of 0 V to +10 V unipolar of ±5 V bipolar, exter-
nally selectable. As the BLANK and CONVERT input is driven
low, the three-state outputs go into the high impedance state
and a conversion commences. Upon completion of the conver-
sion, the DATA READY line goes low and the data appears at
the output. Pulling the BLANK and CONVERT input high
three states the outputs and readies the device for the next con-
version. The AD570 executes a true 8-bit conversion with no
missing codes in approximately 25 µs.
3. The AD570 accepts either unipolar (0 V to +10 V) or bipolar
(–5 V to +5 V) analog inputs by grounding or opening a
single pin.
4. The device offers true 8-bit accuracy and exhibits no missing
codes over its entire operating temperature range.
5. Operation is guaranteed with –15 V and +5 V supplies. The
device will also operate with a –12 V supply.
The AD570 is available in two version; the AD570J is specified
for the 0°C to +70°C temperature range, the AD570S for –55°C
to +125°C. Both guarantee full 8-bit accuracy and no missing
codes over their respective temperature ranges.
6. The AD570S is also available processed to MIL-STD-883C,
Class B. The military data sheet for the AD570SD/883B is
included in the Analog Devices Military Products Databook.
*U.S. Patents Numbered: 3,940,760; 4,213,806 and 4,136,349.
REV. A
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