8
8
8
8
8
r. ANALOG
L.III DEVICES
CMOS
10-BitMonolithicAID Converter
FEATURES
8- and 10-Bit Resolution
20llS Conversion Time
Microprocessor Compatibility
Very Low Power Dissipation
Parallel and Serial Outputs
Ratiometric Operation
TTL/DTL/CMOS Logic Compatibility
CMOS Monolithic Construction
GENERAL DESCRIPTION
The AD7570 is a monolithic CMOS 10-bit successive approxi-
mation AID converter on a 120 by 13 5 mil chip, requiring
only an external comparator, reference and passive clocking
components. Ratiometric operation is inherent, since an ex-
tremely accurate multiplying DAC is used in the feedback loop.
The AD7570 parallel output data lines and Busy line utilize
three-state logic to permit bussing with other AID output and
control lines or with other I/O interface circuitry. Two enables
are available: one controls the two MSBs; the second controls
the remaining 8 LSBs. This feature provides the control interface
for most microprocessors which can accept only an 8-bit byte.
The AD7570 also provides a serial data output line to be used
in conjunction with the serial synchronization line. The clock
can be driven externally or, with the addition of a resistor and
a capacitor, can run internally as high as 0.6MHz allowing a
total conversion time (8 bits) of typically 201ls. An 8-bit short
cycle control pin stops the clock after exercising 8 bits, nor-
mally used for the "J" version (8-bit resolution).
The AD7570 requires two power supplies, a +15V main supply
and a +5V (for TTL/DTL logic) to + 15V (for CMOS logic)
supply for digital circuitry. Both analog and digital grounds
are available.
The AD7570 is a monolithic device using a proprietary CMOS
process featuring a double layer metal interconnect, on-chip
thin-film resistor network and silicon nitride passivation
ensuring high reliability and excellent long term stability.
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 implica-
tion or otherwise under any patent or patent rights of Analog Devices.
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FUNCTIONAL DIAGRAM
OUT1 OUT2
AIN
VREF
CaMP
STRT SUCCESSIVE
APPROXIMATION
lOGICClK
L-221-13l-1l-6T- -l
220 236 16 66
Vcc DGND voo AGND
P.O. Box 280; Norwood, Massachusetts 02062 U.S.
Tel:617/329-4700 Twx: 710/394-65'
Telex: 924491 Cables: ANALOG NORWOODMA:
I
I
10
,..,....--0 DB9 (MSB)
DB8
18
DB1
19
DBO (lSBI
28
BUSY
8
SRO
27
BSEN
20
HBEN
21
lBEN
9
- SYNC
OBSOLETE