My Cyrus PSX original version has unfortunately shorted a couple of its rectifier diodes which were PFR 854's. These are long obsolete and I was hoping someone could recommend a replacement? The originals are 3.5w.
A direct replacement is BYW95C.
Donberg has it but I have no idea if this seller has genuine parts.
Hugo
Donberg has it but I have no idea if this seller has genuine parts.
Hugo
Thanks, if that's a direct replacement at 3w (not 3.5w as origianl) is this part critical, or would any 3w fast recovery diode do, like a 1N5402?
1N5402 isn’t fast recovery. They are probably making a generic FR4502 which would be. I use the FR400x 1 amp stuff all the time now in high frequency application and it’s as good as anything these days.
Thanks, however these replacements seem to be equally un obtainable from trusted places. How about the UF5404?
UF. But I’ve seen both, depending on who’s making them. Pretty much generic these days.
Thats fine. Higher voltage grades can almost always be substituted. They are just as fast. Higher voltage versions usually run a bit higher forward voltage drop. It all depends on how they are binned at final test, and where statistically the batch they started with falls.
Higher voltage types aren't "just as fast" there is a process transition that happens at around 400V that bumps the recovery time up to 75 ns from 50 ns for the UF54xx series. The information is there in the data sheet. Higher voltage types are built with a higher resistivity silicon starting material that affects both the forward voltage and the reverse recovery time. It's all about voltage grading across the reverse-biased diode junction.
Last edited: