INA122 question

Roy wang

Intellectual 775 points

Other Parts Discussed in Thread: INA122

Dear：

INA122 Question：

1.Circuit diagram is as follows，when S-=0V，S+=1V，G=7，VCC=22v，now and then the Vout=22V，

nomoral the Vout should 7V，why？

over 7 years ago

0 Pete%20Semig over 7 years ago

TI__Mastermind 25775 points

Hello Roy,

The INA is operating with a single 3.3V supply and the reference terminal is grounded. When S- is also connected to ground, the device is not operating linearly. Please read the following FAQ for more information:

e2e.ti.com/.../3373.understanding-instrumentation-amplifier-vcm-vs-vout-plots

Please download and install the following tool to help you determine the linear operating region:

www.ti.com/.../ina-cmv-calc

Please note that in your text you state Vcc=22V, but the diagram shows +VS=3.3V. Nonetheless you can verify this by applying 2V to S- and 3V to S+ (assuming a 22V supply) and the output should be 7V.

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INA122 question