#### exp

##### Full Member level 1

I am struggling for long with transistor models of a new process. I get all kinds of weird stuff but specifically: Can the zero of an ordinary diff pair (i.e., Common Source stage) come before the unity crossover?

This is the bode plot I am getting (ac analysis with annotated poles/zeros from pz analysis):

According to hybrid-Pi model, the zero comes from Cgd feedthrough and the zero is given by gm/Cgd

Since Cgd < Cgs (or even Cgg), it must occur after the unity crossover.

Can this really be correct and if yes, why and how? Or can it really be that the transistor model is broken?