Low Cost, Zero-Drift In-Amp
with Filter and Fixed Gain
AD8293G80/AD8293G160
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Small package: 8-lead SOT-23
Reduced component count
7
5
6
+V
FILT
R2
OUT
S
Incorporates gain resistors and filter resistors
Low offset voltage: 20 μV maximum
Low offset drift: 0.3 μV/°C maximum
Low gain drift: 25 ppm/°C maximum
High CMR: 140 dB typical
+IN
8
1
R3
5kΩ
R1
4kΩ
4
IN-AMP
ADC OUT
OUTPUT TO ADC
WITH ANTIALIASING
FILTER
–IN
Low noise: 0.7 μV p-p from 0.01 Hz to 10 Hz
Single-supply operation: 1.8 V to 5.5 V
Rail-to-rail output
GND REF
2
AD8293Gxx
3
Figure 1.
Available in 2 fixed-gain models
+5V
APPLICATIONS
C2
0.1µF
Current sensing
Strain gauges
Laser diode control loops
Portable medical instruments
Thermocouple amplifiers
7
5
6
+VS
FILT
R2
OUT
LOAD
I
+IN
8
1
R3
5kΩ
R1
4kΩ
4
RSHUNT
ADC
IN-AMP
ADC OUT
C3
–IN
REF
+3.3V
1.8V
DC-DC
0.1µF
10µF
GND REF
AD8293Gxx
2
3
Figure 2. Measuring Current Using the AD8293G80/AD8293G160
Table 1. AD8293Gxx Models and Gains
Model
Gain
AD8293G80
AD8293G160
80
160
GENERAL DESCRIPTION
The AD8293G80/AD8293G160 are small, low cost, precision
instrumentation amplifiers that have low noise and rail-to-rail
outputs. They are available in two fixed-gain models: 80 and 160.
They incorporate the gain setting resistors and filter resistors,
reducing the number of ancillary components. For example,
only two external capacitors are needed to implement a 2-pole
filter. The AD8293G80/AD8293G160 also feature low offset
voltage, offset drift, and gain drift coupled with high common-
mode rejection. They are capable of operating on a supply of
1.8 V to 5.5 V.
Precision instrumentation, position and pressure sensors,
medical instrumentation, and strain gauge amplifiers benefit
from the low noise, low input bias current, and high common-
mode rejection. The small footprint and low cost are ideal for
high volume applications.
The small package and low power consumption allow the maxi-
mum channel density and the minimum board size required for
portable systems. Designed for ease of use, these instrumentation
amplifiers, unlike more traditional ones, have a buffered reference,
eliminating the need for an additional op amp to set the reference
voltage to midsupply.
With a low offset voltage of 20 μV (AD8293G160B), an offset
voltage drift of 0.3 μV/°C, and a voltage noise of only 0.7 μV p-p
(0.01 Hz to 10 Hz), the AD8293G80/AD8293G160 are ideal
for applications where error sources cannot be tolerated.
The AD8293G80/AD8293G160 are specified over the industrial
temperature range from −40°C to +85°C. The AD8293G80/
AD8293G160 are available in a halogen-free, Pb-free, 8-lead SOT-23.
Rev. 0
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