Fake IRFP240 !!!

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I've just brought 50pcs IRFP240 fgrom Singapore electronics store, at about USD $1.5 ea. initially I was very happy ,but when I compare it to the others IR product I found that something not right.I can't even read the bacth# and the produce date.

Can anyone tell me the difference between these 2 International Rectifier,I suspect the right hand side the one was a fake IR product... am I correct ??!!How can I test these mosfet to comfirm is it fake.

Any help I will very appreciate.



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The one and only
Joined 2001
Paid Member
It may be that this is not any type of IRFP240, but
setting that issue aside:

A number of alerts to "fake" parts have come up, but
remember that the IR parts are standard types made by
other manufacturers also, and this is no reason to think
that they are not good. If you are building a Zen or Aleph,
it is likely that IRF equivalents will work fine.

Try them out, if they don't work, you're only out a few bucks.


IR is the largest manufacturer of power Mosfets, and I
like their parts because they are quite uniform and the
pricing is very competitive.

but there are unreal second sources...

Here we are talking about a part with a IR marking. If anybody other than a foundry working for the branded manufacturer made it, it is clearly a fake. Here it may be another part by the original manufacturer that the dealer may have confused with a more common part.

However, if another manufacturer makes a part with the same number as the original manufacturer's but marks it with its own logo, it is by definition not a fake. The question is gets to decide that the part is a fully functional equivalent (true second source) and may rightfully bear the same part number?

In the thread http://www.diyaudio.com/forums/show...page=15&highlight=Sanken AND WEC&pagenumber=2 I explained that I had ordered 2SA2837 bipolar power transistors (originally a Sanken multi emitter part with excellent current gain linearity, high gain bandwidth and exceptionally llow collector base capacitance for a transistor with this kind of current and power rating.
I received a part branded as WEC, and low current beta, beta linearity and CB capacitance turned out to be far worse than the spread I had observed on original Sanken part under identical conditions, so these parte went to the junkbox right away without further measurements.

While I never found out what WEC is nor a data sheet by them, Sonny pointed a Taiwanese manufacturer called Mospec out who was also offering a 2SA2837 and who had a data sheet on their web pages. The only ratings that were comparable to the Sanken spec were power and current rating. All other parameters including minimum gain, gain linearity, bandwidth and relevant capacities were inferior by factors!

To me this is a functional fake. You will now it's not the part you ordered when you see it (if you're lucky, your dealer told you it was second source when you ordered, but this is rarely the case) Unless you do extensive qualification or can hunt down the data sheet, you won't know if this is a true second source....

Frustrating, isn't it?

The one and only
Joined 2001
Paid Member
Another wrinkle on this topic is the so-called "functional
replacement" parts offered by a couple of different
outfits. In the old days when I was a fixing Sonys and
Pioneers, it was apparent that these parts were the
"floor sweepings" from the factory. They might work,
but for linear applications they are often not the best

All this brings up the importance of testing the parts
yourself. As DIYers, we have a tendency to agonize
over the quality of our resistors, caps, and wires while
putting up with +/- 100% tolerance on active gain devices.

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