Replacement MOSFETs - Page 1
Forum section: electronics / beginners

author: OpenCircuit
author_rank: Regular Contributor
timestamp: March 27, 2017, 09:03:26 pm
content: I have a few different MOSFETS from different ATX power supplies that I need to find replacements for. One PSU had/has 20N60S1, another 12N50C3 and the third 60R190E6.Ideally looking for a universal replacement part for all three. G, D and S pins are all the same for the three-I believe. Surprised at how expensive these are.I did observe 12N50C3 are 560V and appear to be zenner protected whereas the other two are 600V and not zenner protected. So, not entirely certain about cross-reference.My other concern is gate control? Here are the links if anyone has a second to take a look.Links:https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwj8nqbsx_fSAhVIyoMKHQ-uBCkQFggcMAA&url=http%3A%2F%2Fwww.infineon.com%2Fdgdl%2FInfineon-SPP_I_A12N50C3-DS-v03_01-en.pdf%3FfileId%3Ddb3a3043163797a6011637ecbecd0079&usg=AFQjCNFkTYRCQPVKOJGTX4d1fDEVqWuRJg&sig2=DL4mfaOzRO-M5ADZP1KLPw&cad=rjahttps://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwjPj5_RyffSAhUL7YMKHUDjCHAQFggnMAI&url=http%3A%2F%2Fwww.alliedelec.com%2Fm%2Fd%2F3b3a26d3783676403d681a1f91ce327a.pdf&usg=AFQjCNGZPPhAq6xsgKSzRPhH1Q8IgNstNQ&sig2=EjB7uYPvJoBv_IsUUyHabAhttps://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwj78Z_NyvfSAhUo6YMKHb-VBFMQFggrMAA&url=http%3A%2F%2Fwww.infineon.com%2Fdgdl%2FInfineon-IPA60R190E6-DS-v02_03-EN.pdf%3FfileId%3Ddb3a3043284aacd801286c9f28472921&usg=AFQjCNEOY_79BghqVkPc6MYAFdzytsaGCg&sig2=s8EMdeS6FrQZ4K6wAc35Ag&bvm=bv.150729734,d.amc&cad=rja

author: danadak
author_rank: Super Contributor
timestamp: March 27, 2017, 10:29:52 pm
content: Look at all 3 datasheets, using excel put in key parameters like Rdson, Gate Charge,thermal R's, Vth, breakdown V's, package (must be all same)...If the MOSFETs have significant differences I would suggest crossing to 3 distinct parts,use vendor FAE / tech support to help you.If parts close then using digikey part search tool and set filters to the worst case value for the three.This is risky, especially gate charge issues, because gate driver in supply may be optimizedfor that specific MOSFET, so beware.Regards, Dana.

author: amspire
author_rank: Super Contributor
timestamp: March 27, 2017, 11:51:49 pm
content: I wouldn't substitute mosfets.If you go to Mouser, Digikey, etc and search for the generic part of the name - 20N60, 12N50, 60R190 - you will find a lot of options that can be quite cheap and may be replacements. You have to compare the datasheet to check which ones might work. Getting exactly the same device is the safest, but sourcing one particular part from one manufacturer can be expensive.Little things come into play - like designing snubber circuits that rely on a particular drain capacitance of the mosfet. Substituting a different type of mosfet can invalidate the design. Gate drive circuits designed for one mosfet may not have the capacity to drive another mosfet with higher gate-drain capacitance. If the gate drive is not powerful enough to hold a mosfet off, it may turn on again partially as the drain voltage is rising and this can double or triple the dissipation.