20 Nov
2025
20 Nov
'25
8:24 a.m.
On 11/20/25 08:37, Tom Hunter via cctalk wrote:
I received samples of the 2N5771 and have tested them.
They are perfect
replacements for the 2N3639 . Actually the 2N5771 has the better
performance.
I have also tested the PN4258 which too is a very good replacement for the
2N3639.
Wow, glad you found something that works! I still am
mystified why the MPSH81 was not suitable. You reported a
400 ns turn-on, which seems insane. I have more experience
with the MPSH10, the NPN cousin of the MPSH81, and have
used it in 1 ns risetime circuits.
Jon