9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

The INA12x measure a small differential voltage with a high common-mode voltage developed between

the noninverting and inverting input. The high input-voltage protection circuit in conjunction with high input

impedance make the INA12x an excellent choice for a wide range of applications. The ability to set the

reference pin to adjust the functionality of the output signal offers additional flexibility that is practical for multiple

configurations.

9.1.1 Input Common-Mode Range

The linear input voltage range of the INA12x input circuitry ranges from approximately 2 V less than the positive

supply voltage to 2 V greater than the negative supply. A differential input voltage causes the output voltage to

increase; however, the linear input range is limited by the output voltage swing of amplifiers A1 and A2. Thus,

the linear common-mode input range is related to the output voltage of the complete amplifier. This behavior also

depends on the supply voltage (see Figure 7-6).

Input overload can produce an output voltage that appears normal. For example, if an input-overload condition

drives both input amplifiers to their positive output swing limit, the difference voltage measured by the output

amplifier is near zero. The output of A3 is near 0 V even though both inputs are overloaded.

INA128, INA129

SBOS051F – OCTOBER 1995 – REVISED MAY 2022

www.ti.com

14

Submit Document Feedback

Copyright © 2022 Texas Instruments Incorporated

Product Folder Links: INA128 INA129