AD8231_07 Datasheet, PDF (1/8 Pages) Analog Devices – Zero Drift, Digital Programmable Instrumentation Amplifier

Zero Drift, Digital Programmable
Instrumentation Amplifier
Preliminary Data Sheet
FEATURES
Digitally programmable gain
G= 1, 2, 4, 8, 16, 32, 64, 128
Software or pin programmable
Excellent temperature performance
Specified from −40°C to +125°C
50 nV/°C max input offset drift
10 ppm/°C max gain drift
Excellent dc performance
122 dB min CMR, G = 128
25 μV max input offset voltage
100 pA max bias current
0.7 uV p-p (0.1 Hz to 10 Hz)
Good ac performance
Gain Bandwidth Product 1 MHz
Slew Rate 0.7 V/μs
Rail-to-rail input and output
Shutdown/Multiplex
Additional uncommitted op amp
Supply range: 3.0V to 5.5V
APPLICATIONS
Pressure and Strain Transducers
Thermocouples and RTDs
Programmable Instrumentation
Industrial Controls
Weigh Scales
GENERAL DESCRIPTION
The AD8231 is a low drift, rail to rail, instrumentation amplifier
with software programmable gains of 1, 2, 4, 8, 16, 32, 64 or
128. The gains are programmed via digital logic or pin
strapping.
The AD8231 is ideal for applications that require precision
performance over a wide temperature range, such as industrial
temperature sensing and data logging. Because the gain setting
resistors are internal, maximum gain drift is only 10 ppm/ºC.
Because of the autozero input stage, maximum input offset is 25
uV and maximum input offset drift is just 50 nV/ºC. CMRR is
also guaranteed over temperature: 80 dB for G=1, increasing to
122 dB at a gain of 128. Voltage noise is just 0.7 uV p-p (0.01
Hz to 10 Hz).
Rev. PrC
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AD8231
WR A0
A1
A2
SDN
OUT2
-IN
N
P
OUT1
+IN
AD8231
+VS
-VS
REF
Figure 1. AD8231 Functional Diagram
The AD8231 also includes an uncommitted op amp which can
be used for additional gain, differential signal driving or
filtering. Like the in amp, the op amp has an autozero
architecture, rail to rail input, and rail to rail output.
The AD8231 includes a shutdown feature that reduces current
to 1 uA and makes the amplifier output high impedance. This
allows easy multiplexing of multiple amplifiers without
additional switches.
The AD8231 is specified over the extended industrial
temperature range of -40°C to +125°C. It is available in a 4mm
x 4mm 16-Lead LFCSP (Chip Scale) package.
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