ADC12QM_15 Datasheet, PDF (1/4 Pages) Analog Devices – LOW COST GENERAL PURPOSE ANALOG TO DIGITAL CONVERTER

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LowCostGeneraPl urpose
AnalogT-o-DigitaCl onverter
PRELIMINARY TECHNICAL DATA
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FEATURES
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12 Bit Resolution and Accuracy
Very High Performance/Cost Ratio
Monotonic from OoCto +50°C
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40J,LsConversion Time
Low Profile Module
Parallel and Serial Outputs
TTL/DTL Logic Levels
User Selected Input Ranges
Input Buffer Option Available
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OB _{-~-- GENERAL DESCRIPTION}
S _{The ADC-12QZ is a 12-bit successive approximation type}
O ^{general purpose analog-to-digital converter that offers mod-}
erate speed and good performance at very low cost. Analog
L ^{Devices' proprietary monolithic quad switches and a unique}
combination of thin film and hybrid technology have been
E _{incorporated in the ADC-12QZ, resulting in a converter that}
T ^{has the basic performance of a much higher priced unit. It}
is monotonic (no missing codes) from OoCto +50°C, and has
E a maximum error of :tVzLSBrelative to full scale. The ADC-
I
operation and in offset binary code for bipolar operation. The
STROBE output is used to synchronize the serial data with a
receiving shift register.
TIMING
As shown in Figure 1, the leading edge ("0" to "1" transition)
of the convert command pulse sets the STATUS and MSB out-
puts to the "1" state, and the outputs of bits 2-12 to "0". The
conversion program begins on the trailing edge of the convert
command pulse with the starting of the internal clock. The bit
decisions are made on successive "1" to "0" clock pulse transi-
12QZ is packaged in a convenient, small, low profile module,
tions, with the MSB decision occurring first. The 200ns wide
and all of its logic inputs and outputs are fully TTL/DTL
strobe pulses are used to synchronize the transmission of serial
compatible.
data. Serial data bits are valid on successive leading edges ("0"
EASY TO USE
to "1" transitions) of the strobe pulses. At the completion of
The ADC-12QZ was designed specifically to make it easy to
use. It contains its own temperature-compensated precision
voltage reference, and any of four input ranges (0 to +10V,
:tl0V, 0 to +5V, :t5V) can be selected with jumpers and con-
nections at the module terminals. If a high input impedance is
required, the ADC-12QZ can be special ordered with an in-
put buffer.
Binary output coding is used for unipolar operation, but for
operation in the bipolar mode, the parallel output data can be
either two's complement or offset binary at the user's option.
The two codes differ only in that the MSB output (pin 72) is
used for offset binary coding, while its complement, MSB (pin
70) is used for two's complement coding. STATUS, which in-
dicates when the parallel output data is valid, and its comple-
ment, STATUS, are both available.
the conversion, the STATUS output returns to zero, signaling
that the parallel output data is valid.
Cg~~ER:..n
PREVIOUS WORD, 0011
.. 0
NEW WORD.
010111101000
..J STATUS
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CLOCK
STROBE
BIT 1
IMSBI
BIT 2
BIT 3
,
BIT 4
BIT 12
ILSBI
SERIAL
OUT
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Figure 1. ADC-12QZ
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Timing Diagram
A latched serial output having a nonreturn-to-zero (NRZ) for-
mat is taken from the output of a TTL flip-flop. The serial
data is transmitted MSB first in binary code for unipolar
r-'
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.
Route 1 Industrial Park; P.O. Box 280; Norwood, Mass.02062
Tel: [phone]
TWX: 710/394-6577
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