May I ask you to help me? I want to design a cross coupled oscillator in pspice with 50 mhz frequency. but it doesnt work properly. which kind of mosfet should I use ?
I modified previous simulations of similar oscillators. This one worked after I tried a trick or two.
To get oscillations to build, I found I had to make the inductor-to-capacitor ratio very high (11,000). This is to accommodate the low amount of current available to drive the LC tank loop.
When I tried a low L/C ratio, oscillations did not sustain. They faded.
The supply V needs to be high enough as well. The simulation needed 4V minimum. This is just theory, based on the mosfet model in Falstad's simulator.
Thank you for your reply, what is the specification of the mosfets you have used. of course their W/L can have effect on the performance. I am using Pspice for the simulation and I used BUZ10 mosfets, But the oscillation just happens in micro seconds and then again gets to zero, I think maybe the mosfets are not the right one.
Falstad's mosfet model has one parameter we can adjust, 'threshold'. I left it at the default value, 1.5V. (Changing it usually has small effect anyway.)
I am using Pspice for the simulation and I used BUZ10 mosfets, But the oscillation just happens in micro seconds and then again gets to zero, I think maybe the mosfets are not the right one.