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-   -   IRFP240 source? (http://www.diyaudio.com/forums/pass-labs/228281-irfp240-source.html)

oneplustwo 20th January 2013 09:44 PM

IRFP240 source?
 
Are the IRFP240s becoming scarce now? I couldn't find them on mouser or anywhere else "reputable." Any suggestions for where to get these? Maybe my mouser search was bad? Or maybe someone has had good luck with a particular ebay seller? I'm looking to get quite a few so I can match them myself.

jackinnj 20th January 2013 09:55 PM

enter IRFP240pbf in the search engine

MarcelvdG 20th January 2013 10:00 PM

Farnell still has 2439 of them in stock.

oneplustwo 20th January 2013 10:01 PM

Quote:

Originally Posted by jackinnj (Post 3334993)
enter IRFP240pbf in the search engine

Ah, ok. Not a great search engine, is it?! Thanks!

oneplustwo 20th January 2013 10:03 PM

While I'm on the topic... Any guidance on what number you need to purchase to get good matches? Let's say you need to match 4 closely. You need to buy... 20?

Similar question on the IRF9610s although I would guess the answer would be about the same.

jackinnj 20th January 2013 10:19 PM

Depends upon how closely you want them to match -- if you purchase a tube you should get enough devices for 2x 4 sets +/- 0.02V.

I found that within a tube, when you match for Vgs the transconductances generally line up pretty well.

oneplustwo 20th January 2013 10:22 PM

Sorry for the newb question, but how many in a tube?

cochleus 20th January 2013 11:29 PM

Quote:

Originally Posted by oneplustwo (Post 3335027)
how many in a tube?

25 pieces

MEGA_amp 21st January 2013 01:06 AM

I've used these as an alternative to the irfp240, they work pretty well. You should have no problem matching 4pcs within a tube, I'd be skeptical purchasing semis from ebay; matched or otherwise.

FQH44N10_F133 Fairchild Semiconductor | Mouser

Nelson Pass 21st January 2013 01:41 AM

You need matches only for the ones in parallel. Most of the time 0.1V
at the operating point is good enough, and you can probably get 5 groups of
4 out of a tube.

:cool:


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