how to make capacitor unchange under different process?HELP

[shanmei]

in the relaxation oscillator, the frequency is strongly depended on the capacitor,
anyone who konws how to make the capacitor unchange under different process.
? how to compensate capacitor under different process? thanks~

 

[mss]

I spent mach time for this problem, and faund that it is imposible. But you can try nmos cap.

 

[Meridian]

Re: how to make capacitor unchange under different process?

in the relaxation oscillator, the frequency is strongly depended on the capacitor,
anyone who konws how to make the capacitor unchange under different process.
? how to compensate capacitor under different process? thanks~

I think your design is flawed (no offense). It is difficult if not impossible to stabilize capacitance. It will always change a bit with temperature, slight voltage variations, and frequency.
The only way to solve your dilemma is to redesign your circuit with a crystal controlled or PLL output (depending on your circuit design).

Can you post a diagram for us to look at, or is it copyrighted?