class b fet

I have a question on how to detemine a bias voltage for class B FET amplifier. If the data sheet have a pinch off voltage. Can I use that? I also did a DC trace and plot Ids vs Vgs. I try to use the Vgs that Ids start to take off but it seems that it does not work for some FET? any sugestion how to find a good bias point for FET. I use most Motorolla product since it has a design kit in @DS. some FETs in there I can do class B but some i cannot. The waveform is not look nice as in Crips book. I have try Crips book statz model in Crips book in @DS. It look very good. I dont know how good is statz model copare to motorolla design kit model? any sugesstion?

Your best bet for class B bias would be to adapt a veriable voltage ajustment to bring the FET into conduction. You would then be able to control the crossover distortion . I believe the last complimentry pair of FETs I set up were biased to 70 ma drain current.

Barrybear