measuring DC offset of differential amplifier

[matin-kh]

Hi every one
I want to measure DC offset of a differential amplifier in cadence spectre and untill now i understood i should use monte carlo to simulate but I have no idea how i can use it and how to measure dc offset.
could you please help me?
best regards
matin

 

[Dominik Przyborowski]

You have to measure differences between both inputs for any closed loop configuration, e.g. as voltage follower.
If You want to get a histogram of offset You need to use expression like VDC("/in+")-VDC("/in-").

In virtuoso 6.x any MC simulation You are doing in adexl view.

 

[dick_freebird]

I always use a vcvs to take the input difference voltage
and create a single ended ground referred value. Also use
that voltage in my own gain/phase plots, having found
the iprobe / stb to be unreliable (not often, but often
enough to ruin a MC run consistently, no idea why and
no way to tell whether - except when you get whacked
outliers).