AD1175_15 Datasheet, PDF (1/8 Pages) Analog Devices – HIGH ACCURACY 22 BIT INTERGRATING A/D CONVERTER

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~ DEVICES
HighAccuracy2,2-Bit
IntegratingAIDConverter
FEATURES
High Resolution: 22 Bits
Wide Dynamic Range: 133dB
Low Nonlinearity:
Integral: :t 0.5ppm max
OBSOLETE Differential: :t0.5LSB max
High Stability:
Gain: :!:1ppm/oC max
Zero: :to.5J.lVrC max
INL: :to.01ppmrC
DNL: :!:O.OO25ppm/oC
High Throughput Rate: 20 Conversions/Second
Microprocessor Compatible Interface
Compact Modular Package
APPLICATIONS
Data Acquisition Systems
Scientific Instruments
Medical Instruments
Weighing Systems
Automatic Test Equipment
Test and Measurement Equipment
Several modes of operation are available and allow writing to
one of several addressable locations to program gain and offset,
or to initiate a conversion.
The AD 1175 requires no external components and operates
from:!: l5V de and + 5V de power. All digital inputs and outputs
GENERAL DESCRIPTION
are LSTTL compatible. The 3.7" x 5.2" x 0.53" metal case package
The AD 1175 is a very high resolution integrating A/D converter
provides excellent electrostatic and electromagnetic shielding.
intended for applications that require the highest possible accuracy
without sacrificing conversion speed, board space or modest
PRODUCT HIGHLIGHTS
pricing. This converter provides the performance of large bench top
I. The unparalleled dynamic range, accuracy, linearity and
or rack mount instruments in a compact, modular package.
stability of the AD 1175 represent a breakthrough for an A/D
The AD 1175 utilizes an auto-zeroed, multislope, integrating
principle that features 22-bit resolution with extremely low
converter offering small size and modest cost. Only large,
expensive bench top meters offer similar performance.
nonlinearity (Integral: :!:O.5ppm max and Differential: :!:O.5LSB
max). Temperature stability is specified at :!:O.5ppmrC maximum
2. The AD1l75 converts approximately ten times as fast as
digital meters with like performance.
for gain (exclusive of reference), :!:0.5ILV/oC maximum for zero,
:!:O.OlppmrC for integral nonlinearity, and:!: 0.0025ppm/oC for
differential nonlinearity.
The integration time is user selectable for maximum, line frequency
noise rejection at either 60Hz or 50Hz. The conversion rate is
20 or 16 per second respectively, which is many times faster
than benchtop instruments of similar performance.
The nominal full-scale input range is :!:5V; however, rated
accuracy is specified for inputs up to 10% over nominal, yielding
a total dynamic range of greater than 4.6 million to I. The
analog input is a high impedance, high CMRR, true differential
input pair. The input low operates within:!: 100m V of analog
ground and is used to sense signal low (at the source) to minimize
ground loop problems.
The output of the AD 1175 consists of four addressable 8-bit
bytes (STATUS and 3 DATA) presented at an 8-bit tri-stated
3. The microprocessor interface of the AD1175 provides for
straightforward operation, but with the features required for
optimum system performance. Simple commands control
offset adjust, gain adjust, external offset null and initiate
conversions. The output bytes indicate input polarity, off-scale
condition and a variety of additional status information.
4. The AD 1175 is a complete A/D converter including a precision
internal reference, clock and integration capacitor. Offset and
coarse gain adjust are bus controlled, while user accessible
trim potentiometers allow fine gain adjust and:!: full-scale
balance adjust.
5. Conversions may be made using either the offset and coarse
gain settings stored in internal nonvolatile memory, or new
settings made via the bus. The nonvolatile memory may be
updated on command with the new settings.
port with standard chip select.
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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