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Low power mosfet replacement problem Answered

Can anyone help me identify a substitute for a mosfet? It is used, as far as I can tell, as a low power DC switch. It is a 6 legged SMD beastie, part number FDC654 - possibly with a P on the end and is completely short circuit. I'm assuming I've got the right device. There is some information about it here: http://www.fairchildsemi.com/pf/FD/FDC654P.html
I can't find anywhere to buy this component as an amateur, and don't know enough to work out a suitable replacement. Can anyone help?


It may be tricky to find another P-channel, enhancement mode, mosfet, in that exact package, the 6-pin SuperSOT.

A package like T0-220 (large, 3 pins) is much more common. 

Assuming you want to attempt such a substitution, and try and cram this larger part into the small space it came out of, the next trick is picking a mosfet with parameters that are close enough for your application.  The three most important parameters are: that it be a mosfet, and that it be P-channel, and that it be enhancement mode, just like the transistor (FDC654 ) that was there in the first place.

After that the most important parameters are probably going to be the maximum drain-source voltage, maximum drain-source current,  on-resistance, input capacitance, etc, etc.

It helps to have some place, er online catalog, that lets you search through their parts parametrically.  Two example part-mongers who have such a parametrically searchable catalog:
For example at Jameco, I found your part, but not available in small quantities, here:

Using the parametric search, I found this, kinda similar, but different p-channel, enhancement mode, mosfet,  for like 1 USD per unit.

I don't know if that mosfet (IRF5305PBF) would actually be a suitable replacement for your thingamajig, whatever it is, but you know, this is just an overview of how you use these companies' catalogs to compare the parameters of parts that are out there.     

Thanks for this - I'll get looking at the catalogues of some UK companies then. It's used as the main switch in a DC supply input from a wall-wart, and has a very low on resistance and optimisation for battery environments as it's main features. I didn't know about parametric searches, so that should be useful.
Many thanks.

Glad I could help.  You know, Seandogue kind of makes a good point too.  The manufacturer might be willing to sell, or give you some free samples of, this exact part.  I think they even have a sales office on the same island you live on,  in some place called, ?Wiltshire?.


Fairchild Semiconductor Ltd
Interface House
Interface Business Park
Wootton Bassett Swindon
Wiltshire England
Tel: 44-1793-856856
Fax: 44-1793-856857

I just tried requesting a sample from the Fairchild site - my request was denied :-(
I'll try ringing the UK office though (Wiltshire is a county, btw, and the town is Swindon) and see what happens. It never even occurred to me.

Um, there's a 'buy' button right on the page.