I'm designing a State Variable Filter design using switched capacitors to control cut-off and resonance. Simulating this using idealized switches yields excellent results. See attached schematic
After that I proceeded to replace one of the integrators with a MOSFET version (the center-right part of the circuit). This doesn't work. I'm using a parasitic-insensitive switched cap implementation as you can see. See attached schematic
I tried a couple of implementations for the switches. First of all the parasitic sensitive version, and after that several parasitic-insensitive versions like this one. I've also tried several different NMOS models.
Can anybody tell me what I'm doing wrong here?