TME replacement for STY60NK30Z MOSFET ?! - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: May 30, 2023, 02:03:20 am
content: Hi all,I'm trying to repair an amplifier and it has this MOSFET which measures short in all directions.It's out of stock at the shop I'm trying to buy it from and I'm unsure what could be a suitable replacement so I thought I'd ask here for some help.This amp is a very high current one so I don't want to cause any further trouble!Here is the link for said mosfet.https://www.tme.eu/gr/en/details/sty60nk30z/tht-n-channel-transistors/stmicroelectronics/I thought that this one might do the trick but I'm not 100% sure:https://www.tme.eu/gr/en/details/ixfq50n60p3/tht-n-channel-transistors/ixys/

author: PartialDischarge
author_rank: Super Contributor
timestamp: May 30, 2023, 02:52:54 am
content: I would not use the ixis at it has 3 times Rdson.Why don’t you get it from digikey?

author: belzrebuth
author_rank: Frequent Contributor
timestamp: May 30, 2023, 09:36:20 am
content: Digikey is not an option.I only buy from Mouser and TME.Mouser had almost double the price for the original transistor so I stayed at TME.Is there anything I can find at that shop that fits ?

author: belzrebuth
author_rank: Frequent Contributor
timestamp: May 30, 2023, 09:55:13 am
content: I found that one:https://www.tme.eu/gr/en/details/ipw60r099p6xksa1/tht-n-channel-transistors/infineon-technologies/which has a 20V gate to source voltage instead of 30V the STY60NK30Z has.But on the schematic is shows a ixfr90n30 instead of STY60NK30Z which also has 20V gate to source voltage and double the current capability. On the schematic I see a 15v zener as gate to source potential so I guess this spec is good for the one I chose no?

author: wraper
author_rank: Unknown
timestamp: May 30, 2023, 09:58:21 am
content: Are you just taking random MOSFETs as possible replacements? They are nothing like with 2x higher voltage rating and thus much higher On-state resistance.

author: wraper
author_rank: Unknown
timestamp: May 30, 2023, 10:15:58 am
content: LINKIt's about all that TME has that is suitable with some further verification, for not too high gate charge in particular. I'd buy at Mouser instead if have some parts to bundle with to get free shipping.

author: belzrebuth
author_rank: Frequent Contributor
timestamp: May 30, 2023, 10:16:48 am
content: I just check that voltage and current ratings are better or equal but as I stated I'd appreciate a little help on choosing the proper one.I've never had to replace a power mosfet that's why I started this thread and filed it under the beginners section.

author: belzrebuth
author_rank: Frequent Contributor
timestamp: May 30, 2023, 10:20:59 am
content: I think I'm going with this one as the original package is also TO247.https://www.tme.eu/gr/en/details/ixth88n30p/tht-n-channel-transistors/ixys/Seems like on resistance is what I was forgetting about.I will have it in mind next time.Thanks.

author: wraper
author_rank: Unknown
timestamp: May 30, 2023, 10:36:19 am
content: Quote from: belzrebuth on May 30, 2023, 10:16:48 amMaximum current is a quite pointless figure in general as it's at rated at conditions which require extreme cooling. It has more meaning for low power parts but for high power parts like these you should primarily look on on-state resistance as it's what primarily dictates actual heat created/dissipated by component.

author: belzrebuth
author_rank: Frequent Contributor
timestamp: May 30, 2023, 10:41:30 am
content: That makes a lot of sense! Thanks for taking the time to clarify.I'm also looking the gate charge characteristics you mentioned; always nice to see how things we know in theory apply in real world applications.I thought gate charge was something worth considering in an analog design small signal scenario.

author: wraper
author_rank: Unknown
timestamp: May 30, 2023, 10:58:17 am
content: Gate charge is important in fast switching applications. As it's what dictates how hard MOSFET gate is to drive and if gate driver circuit will be able to switch it fast enough. Also higher gate charge causes more stress on the gate driver.