Counterfit Parts

[alan sailer]

A friend of mine is also interested in electronics and really enjoys getting a deal. He wanted some IRFP260 devices
for a project and bought some at a great price off Ebay. From China. Two sets from different vendors.

He suspected that the parts were not right and gave them to me to get X-rayed at work. The machine was down
so he had to wait.

A few days ago I looked up how to dissolve the epoxy casing on chips and it sounded fun. Concentrated sulfuric acid at 200C.

Today I got done with the last device of three and the results were interesting.

The real IRFP260 from a real vendor measured 5.1nF. The die was 58500mils^2. (that's thousandths of an inch square).

The first fake 260 was 1.3nF and 18000mils^2.

The second was 0.84nF and 9800mils^2.

The prices he paid were 0.8$, 1$ and 2.50$. So even the lower priced parts were not a deal percentage wise.

To first order the capacitance and the die area tracks nicely. Another feature was the heat-sink. The fake parts had metal
that was much thinner and smaller in area. Although all three metal tabs were copper.

I know that fake parts is not a new concept around these forums. But it was still sort of interesting to see haw really bad
it can get. I can only hope none of this crap ends up in anything important.

I also find it depressing that people are actually spending time and ingenuity making and selling such sad scrap. It makes
me glad that my career was on the up and up. I never lied to ship a part.

Cheers.

[MRMILSTAR]

I've reached the point where I won't buy any active electronic devices from China. there are just way too many fakes. The ones that I have had success with are high voltage diodes but that's as far as I will go. Any sort of transistors I will only buy from US suppliers.

[futurist]

I had similar experience when I bought a bunch of 40N60 TO-247 IGBTs off ebay from china
I dissolved epoxy in conc. nitric acid, and revealed die was significantly different from genuine 40N60 which I got from Hydron, if I remember correctly they were ordered from farnell

I have photos somewhere, I'll post them if I find them. Did you make x-ray photos of the parts? It's much more convenient than decapping silicon with acid

[Mads Barnkob]

Hydron wrote about buying 75N60's a while ago: https://highvoltageforum.net/index.php?topic=193.0

[oneKone]

Unfortunately TO-247 are imo the most faked components in this hobby. I think I've ordered from 20+ vendors in hoping to find one that actually works. Eventually I gave up and started ordering bricks/igbt modules, I have seen fakes but they're obvious with the lower price attached to them.

[alan sailer]

futurist,

I would have loved to do x-rays but the machine at work was broken. I basically did the acid because I was interested in getting the data.

Once again, this is not news to experienced people on this forum. It was just kind of fun for me.

On a side note I did buy some SKM100 form a Chinese source for my last project. They apparently work just fine. I'm not stressing them in
voltage but the current is 5.5X the maximum spec.

Cheers.

A side note: this post would not load until I tried again.

[Hydron]

As mentioned in my post on aliexpress FGY75N60s, I think I was at a large advantage due to the fact that the IGBTs were one of the cheaper parts available in "Power TO247" packages in the first place, reducing the options for faking them by re-labelling the cheapest thing they could find (though it doesn't stop other methods of cheating, like making fake parts from scratch). That was also a few years back, situation could have changed significantly since.

[Hiemal]

As a general rule, I don't buy any parts from aliexpress/ebay from china that still "work", in a sense that the part is still the basic component it claims to be. I.e. a MOSFET can still be a MOSFET, and appear to work, but is a completely different die inside the package.

Digital items that either work or don't are less suspect. Arduinos, micros, digital sensors, etc. The only thing you need to pay attention to is getting knockoffs, that still perform the same. Like, receiving a Gigadevice STM32 micro instead of a true ST part; it still does the same thing, but it's a knockoff.

There's also lcsc.com which lets you source chinese products reliably. I've purchased from them many times in the past and you always get exactly what you ordered, no counterfeits. Funny thing is you can actually order knockoff parts from them too!, and they're almost always better than the same knockoffs you'd buy from ebay or aliexpress.

[johnf]

All they need to do is buy cheap lesser spec'ed overrun parts from a legit maker and remove the markings and put new laser marked part number on from an expensive part.
Measuring Gate capacitance is easy for Fets not so reassuring for IGBTs of course.
Once upon a time I worked for a very large electronics company and one line of products we made were 2 way radios (RT's) for trucking firms Taxis and law enforcement for worldwide sale.
We had several of our designs copied in an Asian country and sold at much cheaper prices worldwide. We then started making fake parts ourselves this involved a cmos 4013 all the markings taken off legs then bent around the other way and circuitry put around it to make it look like a well known Switch mode controller IC. WEe marked these ourselves with a commercial inkjet printer that used uv cure. You guessed it our design was copied and they were having terrible trouble making it go. It would not work with the unitrode part, they asked us for spares and we sold them a few hundred parts for many many terns of dollars each. Our vendor mark on our fake parts looked like the Signetics logo who never made items like tis

[futurist]

Interesting story

You reminded me of a similar story on local elektronika.ba website
Owner of the site designed nixie clock and wanted to sell kits on elecrow. He sent them the schematics, PCB design files and photos of the assembled clock but they wanted him to ship assembled clock to China so they can copy it. At the end he decided to sell PCBs only

https://www.elecrow.com/warm-tube-clock-v2-pcb-board-p-1154.html
https://www.elektronika.ba/forum/viewtopic.php?f=25&t=15843#p148842