In the data sheet of a 400 MHz transistor I found fall time = 60 ns. Clearly these are contradictory specifications
- trise and tfall should be at least an order of magnitude shorter.
Should I believe that fT is specified correctly? (e.g. 2SA2088FRAT106Q transistor).
Apart from the difference between saturated switching and small signal amplifier operation, do you understand the meaning of fT? It's the frequency where the small signal current gain would drop to unity.