Output

INA21x

Load

Supply

ADC

V+

OUT

GND

IN-

IN+

C

BYPASS

0.01mF

to

0.1mF

+2.7Vto+26V

REF

R

1

R

3

R

2

R

4

INA210, INA211

INA212, INA213

INA214

www.ti.com

SBOS437E – MAY 2008 – REVISED JUNE 2013

REF INPUT IMPEDANCE EFFECTS

As with any difference amplifier, the INA210-INA214 series common-mode rejection ratio is affected by any

impedance present at the REF input. This concern is not a problem when the REF pin is connected directly to

most references or power supplies. When using resistive dividers from the power supply or a reference voltage,

the REF pin should be buffered by an op amp.

In systems where the INA210-INA214 output can be sensed differentially, such as by a differential input analog-

to-digital converter (ADC) or by using two separate ADC inputs, the effects of external impedance on the REF

input can be cancelled. Figure 26 depicts a method of taking the output from the INA210-INA214 by using the

REF pin as a reference.

Figure 26. Sensing INA210-INA214 to Cancel Effects of Impedance on the REF Input

Copyright © 2008–2013, Texas Instruments Incorporated

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Product Folder Links: INA210 INA211 INA212 INA213 INA214