Does anyone have some key things to look for when changing from a N-Channel FET(or Pchannel) which has gone obsolete. Meaning, what are the critical items to search for in the datasheet that will make or break the change to an equivalent part?
It would probably be easier for you to say which mosfet you want to replace and the type of circuit. Assuming it is being used as a switch, gate voltage for fully on, RDSon, max. current, and Vds are important. Gate capacitance and total capacitance can also be important, particularly if the device is needed to switch fast. Package thermal characteristics also come into play, if you change the package.