HI,
anybody has some good ideas to simulate the AC characteristics of the differential opamp with switched capacitor CMFB circuit? Because the switched capacitor has no DC operating point, so how to deal with it in AC analysis?
For simulation purposes you have to replace each S/C unit with a time continuous analogon.
There are specific tables how the different switch arrangements are replaced.
The analog replacements can be modelled with delay lines or controlled sources.
The procedure is described, for example, in
Ghausi/Laker: Modern Filter Design - Active RC and Switched Capacitor.
replace your sc cmfb circuit with some voltage controled voltage sources. connect the differential outputs to 2 vcvs and generate a common-mode voltage.