how to get this plot in OPAMP simulation

[eegchen]

This is result from a OTA simulation. The OTA is a basic folded cascod OTA with differential PMOS input stage,connecting a folded cascode output stage.

The x is Vod( differetial output voltage), the y is Rout.

Any one can tell me how to get this result, How to set up the simulation.

 

[wandola]

I guess u can sweep Vod from a value to another one, than u can calculate the corresponding differential gain...