How does Transition frequency affect a transistor?


I have a customer looking at transistor 2N5886GOS-ND which is showing a transition frequency of 4MHz compared to 0.6MHz in the one being replaced.

He is looking to replace this out of a solid state guitar amplifier.

Anybody know the implications of transition frequency in an application such as this?


There shouldn’t be any. The transition frequency describes how the transistor’s current gain is affected by the input frequency. This is a low pass effect, so frequencies beyond 600 kHz on the original part or 4 MHz on the new one would start to be attenuated. Audible frequency range is 20 Hz - 20 kHz which is far below the transition frequency of both parts. No effects should be noticeable.


I’d offer the observation that faster devices generally increase the risk of high-frequency instability, RF interference, etc. May or may not be an issue, depending on the design and it’s implementation.

That said, it seems likely that such a transistor would be used as an output stage driver, which are/were often paralleled in audio amp applications. In such a case, the chance of problems increases as a result of dissimilarities between a replacement device and its teammates.