Hello
Can some tell me what is common mode voltage of any differentail amplifier. Is it a DC voltage or can be an AC voltage? because input of any differential pair is given as : vi1= VCM+vid/2 and vi2 = VCM-vid/2. what is this VCM AC vloltage or DC voltage or the transient voltage (V amplitude) which we apply for doing transient analysis?

 

Hello
Can some tell me what is common mode voltage of any differentail amplifier. Is it a DC voltage or can be an AC voltage? because input of any differential pair is given as : vi1= VCM+vid/2 and vi2 = VCM-vid/2. what is this VCM AC vloltage or DC voltage or the transient voltage (V amplitude) which we apply for doing transient analysis?

Common mode voltage is a DC or an AC voltage and it is literally common (appearing on both) inputs, in the same polarity.
For example see https://electronics.stackexchange.c...age-stand-for-in-an-instrumentation-amplifier .