Low Cost, Zero-Drift In-Amp

with Filter and Fixed Gain

AD8293G80/AD8293G160

Rev. 0

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FEATURES

Small package: 8-lead SOT-23

Reduced component count

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

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

Available in 2 fixed-gain models

APPLICATIONS

Current sensing

Strain gauges

Laser diode control loops

Portable medical instruments

Thermocouple amplifiers

FUNCTIONAL BLOCK DIAGRAM

1

8

7

5

6

4

OUTPUT TO ADC

WITH ANTIALIASING

FILTER

ADC OUT

FILT

–IN

+IN

R1

4kΩ

R2

R3

5kΩ

OUT

AD8293Gxx

REF

GND

3

2

IN-AMP

Figure 1.

1

8

7

5

6

4

ADC OUT

FILT

I

1.8V

–IN

+IN

R1

4kΩ

R3

5kΩ

+3.3V

10µF

0.1µF

C3

OUT

C2

REF

GND

3

2

IN-AMP

ADC

REF

LOAD

DC-DC

+5V

0.1µF

R2

AD8293Gxx

Figure 2. Measuring Current Using the AD8293G80/AD8293G160

Table 1. AD8293Gxx Models and Gains

Model

Gain

AD8293G80

80

AD8293G160

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.

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.

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.

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.