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Topic: Replacement parts: discontinued  (Read 380 times) previous topic - next topic

lilgeekn

Just a general question. I'm in the process of replacing a few blown MOSFETS in a power supply. The part that were originally used seem to be discontinued. My question is how to find a similar part with matching specs? Is there a data base that is out there or just constant google searches the best way?

The original part is RJK458DPK

Any suggestions would be helpful.

Thanks.

MarkT

Google turns up nothing - sure you got the part number right?  A crisp photo of the markings on the
package could be useful if that is the marking - the font and style might be a clue to manufacturer.
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DrAzzy

Yeah - that part number doesn't appear to correspond to any electronic component.

You need to correctly identify the failed part and find it's datasheet. Search mouser/digikey for some similar parts. Part of the issue is looking over the design to see how much the exact specs matter for the MOSFET, since you likely won't be able to get something identical.
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MarkT

Or provide lots of info on the power supply it came from.....
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wvmarle

Digikey.com has a great component selector, you just need to select the relevant parameters (for a MOSFET you'd start with p/n type, voltage and current ratings). You'll have lots of options.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.


lilgeekn

I apologize for my absence, work always get in the way...
That was my mistake I had a typo in my first post. The part number is RDK4518DPK
The power supply is an ALINCO DM-330mv I was able to find full schematics and layout for this unit. Found a similar part have yet to have the time to put it in. Thanks for the help. Digi key was was helpful... now I'm thinking I got the wrong part altogether. Lol. Revisiting the specs.
Thanks all.

MarkT

Can't find RDK4518DPK, do you mean RJK4518DPK?

Vds = 450V,
Rds(on) = 0.13 ohm,
10V gate drive,
93nC total gate charge.

Any replacement should have at least the same voltage, at most 0.13 ohms on-resistance, not much
more than 93nC total gate charge.  The same package type is useful (TO-3P)
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

westfw

See if a 2sk4518 seems reasonable...
Sometimes for common parts, the letters on the end just vary by manufacturer.

lilgeekn

#9
Jun 22, 2018, 09:55 pm Last Edit: Jun 22, 2018, 09:56 pm by lilgeekn
Well  Westfw I couldnt find the part that you recommended with any search.
But did look up a few parts came across this (hopefully I eliminate any typos this time) :FQA30N40
I compared this part with the RJk4518 that was in the PWR supply. It seems really close. I'm still learning about this stuff so I'm not sure what variables I can have fluctuate slightly and the repercussions of such differences.

Paul_KD7HB

Buy extras because you have not identified the reason for the original devices to die.

Paul

westfw

Huh.  I could swear that I had looked and found datasheets for the 2sk4518 and found something that looked likely to be equivalent.   But I don't see it any more - perhaps I mis-typed a part number that actually exists.
Sorry about that :-(

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