Magnitude and Phase Measurement of a Differential-out Ota in Cadence

[pablomarco]

Hi, I am an engineering student. I need to measure my OTA's open-loop magnitude and phase plot in Cadence. Since I am going to design a differential-output OTA, I am quite confused about how I should implement a testbench for that purpose. I would be pretty happy If you guide me.

Thanks in advance.

 

[BigBoss]

Use an ideal transformer and-if the case of- a coupling capacitor at both output and input side.
Drive from single ended ( one pin is grounded ) and get the response similarly single ended output side.
Or use Ideal Balun.. There are few ways to transform diff-to-single ended

 

[arthorios]

For checking the AC response/stability of a fully-differential OTA, it is better to use the "cmdmprobe" to break the differential/common mode loops together with stb analysis. You can get your open-loop gain by setting the close-loop to one with resistive feedback.
I suppose that with a quick google search you can find the tutorial from Prof. Vishal Saxena about this.