Offset voltage measurement

[rishabh_31ec]

Hi, I have designed an NGCC opamp with a bias voltage applied to gate of
Driver pmos of first stage diff. Amplifier as 52 mv. My question is in order to measure the offset voltage which of the following test bench is correct:

(1) as a voltage follower with 52 mv at non inverting terminal and measure the difference of output voltage and 52 mv.

(2) as a voltage follower with variable dc voltage at non inverting terminal and by varying this DC voltage find output voltage @ variable FCC voltage = 0 v.

Is it correct to use the first option as I have design my opamp @ 52 mv bias voltage of first stage driver to obtain specification

 

[KlausST]

Hi,

I´m not familiar with IC design...

what about an inverting circuit with gain of -10 and read at the output -520mV?
It should be low ohmic if you expect large offset current.

Klaus

 

[se7ensong]

Starts from the definition: "The input offset voltage (V_{os}) is a parameter defining the differential DC voltage required between the inputs of an amplifier, especially an operational amplifier (op-amp), to make the output zero (for voltage amplifiers, 0 volts with respect to ground or between differential outputs, depending on the output type)." (Ref: wikipedia)

So, (2) is the way.