tenso
Advanced Member level 4
I am trying to make the switch capacitor equivalent of a RC passive filter and compare there frequency response curves.
My 3dB frequency for the RC filter is 1KHz where C is 1pF and Req is 159M ohms. I am using an fs of 2KHz and the C1 value comes out to be 0.5pF.
Vin value is 1.65V and clock is 3.3V when it is high. I read that for discrete time variant circuits you had to a PSS followed by PAC. This is the first time I had done both and I am attaching the forms for both analyses
.
I am trying to figure out why my freq response curves are different. Here I plot both the magnitude of the outputs of the RC and the switched cap circuit. The red is the former one and the blue is the latter.
The switched cap (blue) rolls off faster. I was wondering if there was an issue with my design or the simulation settings. It seems the RC constant of the switch cap is larger resulting in smaller 3dB frequency
I was hoping someone here could help me with this.
My 3dB frequency for the RC filter is 1KHz where C is 1pF and Req is 159M ohms. I am using an fs of 2KHz and the C1 value comes out to be 0.5pF.
Vin value is 1.65V and clock is 3.3V when it is high. I read that for discrete time variant circuits you had to a PSS followed by PAC. This is the first time I had done both and I am attaching the forms for both analyses
.
I am trying to figure out why my freq response curves are different. Here I plot both the magnitude of the outputs of the RC and the switched cap circuit. The red is the former one and the blue is the latter.
The switched cap (blue) rolls off faster. I was wondering if there was an issue with my design or the simulation settings. It seems the RC constant of the switch cap is larger resulting in smaller 3dB frequency
I was hoping someone here could help me with this.