i need to use a JFet which has high phase linearity. What are the parameters in the datasheets that could indicate this, in addition to the maximum working frequency? Thanks.
From what I read on teh internetz, phase linearity is
basically Cgd. Use of source-tied field plates to shield
gate from drain seems to be the done thing. So I'd
start with looking at high frequency low noise RF JFETs
which must have low Cgd, that with Rgg sets the
fT/fmax (and low noise means low Rgg).
Thank you all for the questions. @dick_freebird . I checked and I believe you are right. Low values are on high frequency and low power FETs. Basically I have a circuit where the first stage I have to use a jfet to give the characteristics of these components. Initially I went on a MPF102 but it is a component that does not offer good performances in that sense, then I landed on a BF245B which has a lower Cis and Crs and consequently a higher fT. I am currently looking for if there is something even more linear. It will have to drive a transistor like the classic 2n3904. I also have another request. The jfet currently pilots a 2n3904. I'm looking for a transitor that can eventually replace the 3904 but with a base-emitter voltage higher than 6 volts.