I have the following homework problem, and have spent hours looking for an equation to use. I haven't found anything helpful so far and am totally lost! Could anyone help me, please? I have used the AD621 simulator on the Analog Devices website and the data sheet, but I'm not even sure exactly what the professor wants for an answer, which is not unusual.

"Given an AD621 with a differential input of +0.001 VDC and a common mode signal of 2 VDC with a gain set to 100, what will be the output values for Vdiff and Vcomm?"

 

I have the following homework problem, and have spent hours looking for an equation to use. I haven't found anything helpful so far and am totally lost! Could anyone help me, please? I have used the AD621 simulator on the Analog Devices website and the data sheet, but I'm not even sure exactly what the professor wants for an answer, which is not unusual.

"Given an AD621 with a differential input of +0.001 VDC and a common mode signal of 2 VDC with a gain set to 100, what will be the output values for Vdiff and Vcomm?"

Vdiff is will be Vin * Av or 1mV * 100, so the answer is Vo=100mV. Since the AD621 is an instrumentation amplifier and inherently rejects common-mode voltages given how the internal op-amps are configured, then your common mode voltage on the output is 0V.

Ideally of course.

 

Thanks!