Fake Chips

[Cursitor Doom]

Hi all,

Is there any reliable method for testing parts for authenticity? I just
bought a bunch of LM317T variable voltage regs off Ebay (from a dealer
with a solid rep, admittedly - but they could themselves have been
fooled) and would like to know if they're genuine or not, as a quick
search on the net showed there *are* fake LM317s around.

Would one be safe to assume that any fake part would not be capable of
performing at the maximum levels claimed by genuine manufacturers in
their datasheets? For example, the 317 is claimed to be good for 1.5A,
but if mine burn up at say 1.3A, is that a clear indication that they're
fake?

Your thoughts, gentlemen....

 

[jfeng@my-deja.com]

Are you willing to do something destructive? Remove the epoxy packaging and look at the chip. For a popular part like an LM317, you can probably find a picture of a genuine chip (maybe as they were made 40 years ago). Otherwise, you could compare it to a known good part.

Some manufacturers have active programs to find counterfeit parts and libraries of information ueful for identifying thenm (like the way the logos and the numbers got printed). You might contact them with pictures of the packaging and the silicon chip.

My buddy at Intel told me that one of the common problems is "NOS" Mil-spec versions of obsolete parts that were really repackaged pulls. They often seem OK, except that they have a higher wear-out failure rate (apparently, catastrophic infant mortality failures are relatively rare, as are the completely wrong chip which had been re-marked).

A priori, I would not automatically assume a failure at 1.3A instead of 1.5A was sufficient evidence, especially in a "new" design with no history of proper cooling, etc. You might have a case if it failed in a known and mature design.

 

[Phil Allison]

Cursitor Doom wrote:

Is there any reliable method for testing parts for authenticity?

** Authenticity can only ever be proved by tracing the supply path of the device back to the actual manufacturer. Buying from authorised dealers is the only way to be able to do this.

If a device fails to meet specs for the part number, then it is probably "fake". There is no simple test.

I just
bought a bunch of LM317T variable voltage regs off Ebay (from a dealer
with a solid rep, admittedly - but they could themselves have been
fooled) and would like to know if they're genuine or not, as a quick
search on the net showed there *are* fake LM317s around.

** When you buy parts from Ebay, you need to stop worrying about
"authenticity" - cos most of them are not.

FYI: The terms "fake" and "counterfeit" refer to parts that are either rejects or relabelled from another much cheaper type that merely used the same package.



..... Phil

 

[frank]

Cursitor Doom <curd@notformail.com> wrote:

Hi all,

Is there any reliable method for testing parts for authenticity? I just
bought a bunch of LM317T variable voltage regs off Ebay (from a dealer
with a solid rep, admittedly - but they could themselves have been
fooled) and would like to know if they're genuine or not, as a quick
search on the net showed there *are* fake LM317s around.

in my experience with fake parts, they usually have nothing to share
with the real one.
Usually they bother to fake expensive parts (like out of production mosfets
or BJT for example that cost many $$ a piece).
I have fake mosfets that really are inexpensive switching high voltage
parts, even the pinout is different, so it's easy to spot.
BJT are usually much different dies, a quick curve tracer inspection
shows them.
I guess that nobody would really bother to fake an LM317, it's
inexpensive and still in production, so why even think about that?
The only gain would come from marking as LM317 some empty TO-220 parts,
and that would be easy to spot

Would one be safe to assume that any fake part would not be capable of
performing at the maximum levels claimed by genuine manufacturers in
their datasheets? For example, the 317 is claimed to be good for 1.5A,
but if mine burn up at say 1.3A, is that a clear indication that they're
fake?

read the datasheet, most of the values are "typical".

Best regards
Frank IZ8DWF

 

[Cursitor Doom]

On Mon, 04 Apr 2016 07:32:13 +0000, frank wrote:

I guess that nobody would really bother to fake an LM317, it's
inexpensive and still in production, so why even think about that?

You would think so, wouldn't you? But someone's done it:
https://www.youtube.com/watch?v=vlw88Fq5SmA

 

[frank]

Cursitor Doom <curd@notformail.com> wrote:

On Mon, 04 Apr 2016 07:32:13 +0000, frank wrote:

I guess that nobody would really bother to fake an LM317, it's
inexpensive and still in production, so why even think about that?

You would think so, wouldn't you? But someone's done it:
https://www.youtube.com/watch?v=vlw88Fq5SmA

that's what I said... empty case is the only way to gain from fake LM317.
If it even does what's supposed to do, it's not likely to be a fake.

Frank IZ8DWF

 

[Boris Mohar]

On Sun, 3 Apr 2016 23:25:16 -0000 (UTC), Cursitor Doom <curd@notformail.com>
wrote:

Hi all,

Is there any reliable method for testing parts for authenticity? I just

On one chip Acetone took of all the markings in one swipe.

--
Boris

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[Tim Schwartz]

On 4/3/2016 7:25 PM, Cursitor Doom wrote:

Hi all,

Is there any reliable method for testing parts for authenticity? I just
bought a bunch of LM317T variable voltage regs off Ebay (from a dealer
with a solid rep, admittedly - but they could themselves have been
fooled) and would like to know if they're genuine or not, as a quick
search on the net showed there *are* fake LM317s around.

Would one be safe to assume that any fake part would not be capable of
performing at the maximum levels claimed by genuine manufacturers in
their datasheets? For example, the 317 is claimed to be good for 1.5A,
but if mine burn up at say 1.3A, is that a clear indication that they're
fake?

Your thoughts, gentlemen....

Wherever possible I try to source parts from a reliable vendor. In the
USA, that means (alphabetically) vendors like Allied, Digikey, Mouser or
Newark. Companies that buy their parts from the original manufacturer.
I don't mind spending a bit more for parts that I believe will be
reliable, as I like avoiding reworks, and wondering if the problem was
my diagnosis or the new part.

Another theory I have is how subcontractors handle duds. Let's say a
major optical laser maker subcontracts with "Dumb-Luck" electronics to
make 10,000 CD player lasers (optical blocks) for them. Dumb-Luck knows
they have to make 13,000 to come up with 10,000 that meet spec. They
know they are SUPPOSED to destroy any others, but instead sell them as
new "A" stock lasers. They look like real ones, because they are, they
just don't meet spec or work at all, and we have no way of knowing.
They think they are being good businessmen by getting money for their scrap.

Regards,
Tim
Bristol Electronics

 

[jfeng@my-deja.com]

On Monday, April 4, 2016 at 11:46:49 AM UTC-7, Jon Elson wrote:

Ah, yes, the Darkness-Emitting Arsenide Diode, or "DEAD". Seems that was an
April 1st story in a respected electronics trade mag, quite some years ago.
It was a way to get 100% yield out of the foundry!
Jon
I remember seeing the data sheet for the DED in the early 1970s. I think it was from Litronix, but it could have been either Signetics or Monsanto.

 

[Jeff Liebermann]

On Sun, 3 Apr 2016 23:25:16 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

>Is there any reliable method for testing parts for authenticity?

Not reliable, but you can get some clues:
<http://www.aeri.com/counterfeit-electronic-component-detection/>
<https://www.erai.com/CustomUploads/ca/wp/2009_3Detecting_Counterfeit_Electronic_Components.pdf>
<http://incompliancemag.com/article/novel-approaches-for-the-detection-of-counterfeit-electronic-components/>
Checking for differences in package features and labeling is what I
use. It won't determine if the device is authentic, but will detect
if there's something obviously wrong or suspicious. An acetone Q-Tip
wipe is a good way to test the labeling. I'm not ready to buy an
X-ray Fluorescence machine to check for material differences.

Would one be safe to assume that any fake part would not be capable of
performing at the maximum levels claimed by genuine manufacturers in
their datasheets? For example, the 317 is claimed to be good for 1.5A,
but if mine burn up at say 1.3A, is that a clear indication that they're
fake?

Sure. Just build a test fixture for each part and see what it can do.
For individual xsistors, a curve tracer might do. For your LM317, a
load tester. That's fine for large quantities. However, if you just
need a few parts for a repair job, such an approach is impractical. If
you can't afford to buy from a reputable vendor, then I suggest you
buy from two or more eBay vendors, in the hope that at least one of
them might be functional. My luck with this method has been good, but
not perfect. I recently needed some 7812CK (TO-3 package) regulators.
I bought from two different eBay sources and received obvious
counterfeits from both. I then reordered the real part from Mouser,
which worked.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[jfeng@my-deja.com]

On Monday, April 4, 2016 at 12:05:02 PM UTC-7, jf...@my-deja.com wrote:

I remember seeing the data sheet for the DED in the early 1970s. I think
it was from Litronix, but it could have been either Signetics or Monsanto.

The one from Signetics was the Write-Only memory
http://repeater-builder.com/molotora/gontor/25120-bw.pdf

 

[Jon Elson]

frank wrote:

in my experience with fake parts, they usually have nothing to share
with the real one.

Well, I bought some "Xilinx" 9500-series CPLDs from a Chinese outfit, when I
got stuck with a batch of boards and the chip was no longer available.

They mostly worked. I think that they were untested die. A small number,
about 5 - 10% would not accept the configuration - they were totally dead.
If they did configure, they worked fine.

Well, I don't KNOW these were fake, but the fact that I'd never had more
than one Xilinx part ever come up totally dead, lead me to suspect they
were. I have no idea whether these were reject wafers, or somebody got hold
of the masks and made a batch.

Oh, actually, there was one other detail that pointed to fake. There was no
molded-in pin 1 dimple on the chip. All Xilinx parts did have the dimple.

Jon

 

[Jon Elson]

Tim Schwartz wrote:

Another theory I have is how subcontractors handle duds. Let's say a
major optical laser maker subcontracts with "Dumb-Luck" electronics to
make 10,000 CD player lasers (optical blocks) for them. Dumb-Luck knows
they have to make 13,000 to come up with 10,000 that meet spec. They
know they are SUPPOSED to destroy any others, but instead sell them as
new "A" stock lasers. They look like real ones, because they are, they
just don't meet spec or work at all, and we have no way of knowing.
They think they are being good businessmen by getting money for their
scrap.

Ah, yes, the Darkness-Emitting Arsenide Diode, or "DEAD". Seems that was an
April 1st story in a respected electronics trade mag, quite some years ago.
It was a way to get 100% yield out of the foundry!

But, the above scenario was the genesis of Poly-Paks, about 40 years ago.
Floor sweepings, and YOU get to test them!

Jon

 

[John-Del]

On Monday, April 4, 2016 at 4:16:31 PM UTC-4, Chuck wrote:

On Sun, 3 Apr 2016 23:25:16 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

Hi all,

Is there any reliable method for testing parts for authenticity? I just
bought a bunch of LM317T variable voltage regs off Ebay (from a dealer
with a solid rep, admittedly - but they could themselves have been
fooled) and would like to know if they're genuine or not, as a quick
search on the net showed there *are* fake LM317s around.

Would one be safe to assume that any fake part would not be capable of
performing at the maximum levels claimed by genuine manufacturers in
their datasheets? For example, the 317 is claimed to be good for 1.5A,
but if mine burn up at say 1.3A, is that a clear indication that they're
fake?

Your thoughts, gentlemen....
Back in the late 90s there was a company called Surburban Electronics
that sold fake STR regulators that didn't regulate and supposedly the
switching transistors used in Sony tvs. The fake transistors set on
fire in under a second. Still don't understand why it was worth
counterfeiting such cheap parts.

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Suburban still exists IIRC, I just don't buy from them unless it's an obsolete flyback or something obscure.

I will buy cheap ICs if they're current production but sell in small quantities, such as LED controllers and such. Some devices I would hope are just not worth the trouble to counterfeit. Simple three legged devices like transistors, IGBT, mosfets etc are too easy to counterfeit that I won't buy them generically unless I simply cannot source them from a reputable supplier.

Speaking of Sony, how many MCZ3001 smps controller chips have you seen destroy parts as soon as power is applied? The only reliable source I know of is B&D Electronics. Supposedly, Electronica also has reliable MCZ3001 chips but since these TVs are pretty much gone, it's no longer a big deal.

 

[Chuck]

On Sun, 3 Apr 2016 23:25:16 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

Hi all,

Is there any reliable method for testing parts for authenticity? I just
bought a bunch of LM317T variable voltage regs off Ebay (from a dealer
with a solid rep, admittedly - but they could themselves have been
fooled) and would like to know if they're genuine or not, as a quick
search on the net showed there *are* fake LM317s around.

Would one be safe to assume that any fake part would not be capable of
performing at the maximum levels claimed by genuine manufacturers in
their datasheets? For example, the 317 is claimed to be good for 1.5A,
but if mine burn up at say 1.3A, is that a clear indication that they're
fake?

Your thoughts, gentlemen....

Back in the late 90s there was a company called Surburban Electronics
that sold fake STR regulators that didn't regulate and supposedly the
switching transistors used in Sony tvs. The fake transistors set on
fire in under a second. Still don't understand why it was worth
counterfeiting such cheap parts.

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