MJE15032/33 Genuine or Fake??

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I recently bought some MJE15032/33's from a local shop in Gurgaon(0.3$ each).
I noticed that there was a difference in the appearance of the two, MJE15032 looks like it's printed using stencil or something and on MJE15033 its more of a look like its engraved, also different in the datasheetsfrom ON semi's. Wasn't sure if these were fake or genuine so I broke them open. Now, after looking at the die's of the two it appears that MJE15032 are fakes and 15033 are genuine. Anyone who also come across these fake devices. Any advice is most welcome.



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1) both transistors shown look genuine, although using slightly different process.
The 15033 has "pitted surface" tab, brighter (looks like nickel) and visible copper has been punched with a flattening tool, which leaves lots of "needle pricks" .
The 15032 has duller tab , looks tinned, visible copper is free of pin pricks.
Anyway the transistor die looks the same, and is tin soldered on both.
Fakes are usually covered by a drop of white substance, looks like epoxy but is somewhat elastic.
Some kind of silicone?
Look at:
Transistores Falsificados.
Counterfeit Transistors
Thanks all for your input. At least now I am rest assured to use these devices and continue to purchase from that shop. He's been serving me for past 10 years and almost none of the devices he gave have failed till now. I made an amplifier for my cousin using 2n3773's i bought from that shop, and that amplifier is working great from last 7 years even after taking a lot of abuse and is often pushed hard.

Thanks & Regards,
Is Beryllium oxide still used in semiconductors to aid heat transfer ? I've not seen mention of it for years now.

If it is then devices should never be cut open as the dust produced is highly toxic.

I doubt BeO is used in RoHS compliant devices. That's one of the things they wanted to get rid of. These are the G types. They probably don't have it in fakes either because it's an extra expense to put in a heat spreader.

The die is the right size, the flange is copper, and the passivation and die attach processes are good (when trying to break it apart, you end up cracking the die because everything is well-bonded). Fake is highly unlikley.
Dear Aniket,

I live in Lucknow and too require the transistors under reference. Can you give me the address of the shop so that I can request him to send the transistors by post.


Hello Katiyar,

I bought these from a local shop in Gurgaon(Haryana), near Delhi. It wont be a good idea to post from Gurgaon to Lucknow. The guy on the shop also offered me ST branded 15032/33.:eek::eek:
Better you could get free samples directly from ON semiconductor. only you have to pay for shipping. Another option is order online from RS components, they have decent price and have a warehouse in India too, shipping is free. Element14 is also a good supplier, you could get free shipping for a decent number of components.

Recently bought MJE15032/33 from a local electronics shop, surprisingly the MJE15033 was labeled "F" meaning manufactured by Fairchild. I know these are made only by On semi. still out of curiosity i bought them for 2$ a pair.
Measured these on the hFe tester on the multimeter. The 15032 read 110~125 for the lot and the 15033 didn't read anything, the DMM displayed 1.
So, I broke them open to see what's inside. the die of 15033 marked "F" was huge compared to the 15032, which was a On semi part.
To me both are fake. Any thoughts??


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today i bought mje 15032 and mje 15033. one is made by isc and other has no label of brand only mje 15033 print on it.legs are thin too and bad printing on it.price is 80rs per pair.i will throw these fake transistor on mouth of shopkeeper.

Inchange Semiconductor (ISC) has one of the most extensive semiconductor lines in the industry. All ISC semiconductors are guaranteed to meet or exceed original parts. ISC is one of the largest manufacturer for replacement semiconductor, could offer discontinued, obsolete, hard to find parts, diminishing source discrete semiconductor. They will remain in ISC’s production as long as there are customers’ demands, even if there is one customer and the demand is small.

Inchange Semiconductor,Power Transistors,Transistor Manufacturer

It's up to you now. Throw them or keep them. ;)
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