Possible fake Toshiba/Sanken transistors?

[SSassen]

Alright, I'm working on a couple of new designs and have purchased some transistors from two local suppliers, these are companies, hence not private individuals. These transistors are offered as original Toshiba/Sanken transistors.

I however have my doubts on whether these are original, the fact that they come supplied in a plastic bag, rather than a plastic tube like original Sankens, has gotten me a little worried. The original Sanken's pictured below (STD03P/N) were bought from Profusion in the UK, a certified dealer for Sanken.

2SJ201/2SK1530 supplied in a plastic bag



Full size image, click to open: http://hardwareanalysis.com/images/a...arge/12207.jpg

Original Sanken STD03P/N supplied in a plastic tube



Full size image, click to open: http://hardwareanalysis.com/images/a...arge/12206.jpg

And now for the possible fakes, they all are printed Toshiba, all seem to have the proper markings on them, but if you look closer the printing all seems different, as the fonts are not the same, the line width differs etc.

Possible fake Sanken MN2488/MP1620



Full size image, click to open: http://hardwareanalysis.com/images/a...arge/12203.jpg

Possible fake Toshiba 2SC5200/2SA1943



Full size image, click to open: http://hardwareanalysis.com/images/a...arge/12204.jpg

Possible fake Toshiba 2SJ201/2SK1530



Full size image, click to open: http://hardwareanalysis.com/images/a...arge/12204.jpg

Now I've had 2SC5200/2SA1943s before that were not manufactured by Toshiba, they were manufactured by ISC (isc,inchange Semiconductor Company Limited Welcome You) but they were stamped 'ISC' and hence it is clear they are not genuine.

But how about these, what do you guys think? I've bought quite a few of each (25-pcs) and I can send them back if I can prove they're indeed fake.

Looking forward to your replies!

Cheers,

Sander Sassen
Hardware Analysis - Computer hardware news, reviews and forums that provide help and assistance with problems.

[SSassen]

After having found the datasheets for the Sanken MN2488/MP1620 one thing is immediately apparant, the equivalent circuit as documented in the datasheet shows there's a resistor between B and E pins on both the NPN and PNP transistor, hence a simple check with a DVM should tell us whether these are genuine or not. However there's one catch, is that equivalent circuit meant to illustrate the device in use, or not?

Equivalent circuit MN2488, other transistor is the PNP equivalent



Measuring the transistors however shows no resistor between pins B and E on either the NPN or the PNP, not even at 10x the value, hence is the datasheet outdated and has the device been changed? Or are these simply fake?

Cheers,

Sander.

[richie00boy]

The equivalent doesn't show a resistor between the device external base and emitter terminals though.

[SSassen]

Ah yes, of course, why didn't I see that on first glance? That actually simplifies things, as with the DVM on diode setting you should only see one PN junction, as the ~70-ohm is less of a voltage drop than the second PN junction. I just verified this and there's indeed just a single diode drop from B to E. So I guess these might afterall be genuine?

Cheers,

Sander.

[kevinkr]

You may simply have gotten devices that because of the limited quantity purchased were bulk packed by the vendor.

Repacking for small quantity orders is a pretty common practice and may also help with shipping expense as it allows the use of a compact square box instead of a long rectangular box.

[kimbo]

The only way to be really sure is to sacrifice one and break it open......check out the size of the silicon die. If it is really small then it is a fake.

I don't know the size for 2SJ201/2SK1530 but Rod Elliots site Counterfeit Transistors
will give you a rough guide. you could of course open a good one for comparison but it would be painful to destroy a genuine part. Ouch!!

[SSassen]

On the 2SJ201/2SK1530 MOSFETs it should be possible to note down capacitances between pins, and compare to someone else's 2SJ201/2SK1530, anybody care to whip out his capacitance tester and a pair of MOSFETs? Here's what I got on mine (averaged on 10 transistors of each type).

Pinout 2SJ201/2SK1530



2SJ201 MOSFET capacitances

- Csd : 2.08nF
- Cgs : 4.25nF
- Cgd : 4.25nF

2SK1530 MOSFET capacitances

- Csd : 1.54nF
- Cgs : 1.60nF
- Cgd : 1.72nF

Cheers,

Sander.

[kevinkr]

Where did you get these parts from? Group buys from mystery sellers here on diyaudio can be a bit risky, but if you bought them through a regular distributor they should be able to provide evidence of their origin.

[SSassen]

If I repeat the same exercise for the possible fake Toshiba 2SC5200 I arrive at the following values (again averaged over 10 transistors).

2SC5200/2SA1943 pinout



Possible fake Toshiba 2SC5200 capacitances

- Cbe : 6.23nF
- Cbc : 0.68nF
- Cec : 0.61nF

I also managed to find a few of the ISC branded C5200 transistors I mentioned previously and if measure those in the same way and average their results I find the following values.

ISC C5200 equivalent transistor



Click for full size image: http://hardwareanalysis.com/images/a...arge/12211.jpg

ISC C5200 capacitances

- Cbe : 6.28nF
- Cbc : 0.71nF
- Cec : 0.60nF

These values are pretty much identical, which would indicate that these have somewhat identical dies? I'm no semiconductor manufacturing process specialist, I'm just an engineer that uses the end product, hence I don't know what conclusions can be drawn from the results?

Cheers,

Sander.

[SSassen]

Kevin,

They come from two distributors here in Holland that supply retailers and repair shops with spare parts, both electronics as well as mechanics and just about everything in between (from replacement parts for your dishwasher down to semiconductors used in A/V equipment). At this point I prefer not to disclose who they are, as the jury is still out on whether these transistors are genuine or not.

Profusion in the UK provides the genuine article, absolutely no question there, I've bought from them before. Actually I have an order in for some Toshiba 2SC5200/2SA1943 transistors with them already just to ease my mind and have some transistors to compare to (they are more expensive than the ones I bought elsewhere though). Unfortunately they do not stock the Toshiba 2SJ201/2SK1530, nor the Sanken MN2488/MP1620.

Cheers,

Sander.