Hi to all!
I just received a BurrBrown OPA2134 opamp but it looks so strange...
here's a shot:
(https://i.ibb.co/d0gySz7/IMG-6907.jpg) (https://ibb.co/svHrhMt)
The other ones that I always have looks in this way:
(https://i.ibb.co/4Khy8FJ/IMG-3523.jpg) (https://ibb.co/jbnKy8H)
As you can see they looks very different.
So...what do you think about the first chip? Genuine or Fake?
Thanks
Smells bad I guess.
Quote from: bool on August 30, 2019, 08:42:40 AM
Smells bad I guess.
Thanks for feedback...
Some other opinion???
Probably fake.
Try it.
MC
Quote from: italianguy63 on August 30, 2019, 09:05:06 AM
Probably fake.
Try it.
MC
Tried, it works but it could probably can be a rebrand dual opamp.
The seller write "GENUINE" but...
Thanks for feedback...
Other opinions???
interesting ....... if you type the serial number [and burr brown] from the possible fake into duckduckgo, it returns opa2134. but, the real serial number does too.
some manufs have a searchable database of their serial numbers so you might get some clues there. see what burr brown websites list for their logos and markings. datasheeets will show dimensions and case outlines, indents and pips, etc. for comparisons.
edit: if the counterfeiters used the R in a circle next to the BB in a box logo, fewer people wold look twice at their fakes. mind, they'd have to have the print centred and square.
Quote from: duck_arse on August 30, 2019, 10:09:47 AM
edit: if the counterfeiters used the R in a circle next to the BB in a box logo, fewer people wold look twice at their fakes. mind, they'd have to have the print centred and square.
Unfortunately no way to check... BB site is down because TI bought them as I read...
BB have been under TI for some time now.
Do current TI former BB chips have BB or TI logo?
Quote from: anotherjim on August 30, 2019, 04:40:02 PM
BB have been under TI for some time now.
Do current TI former BB chips have BB or TI logo?
The BB logo is still used afaik. This one is from a few years ago:
(https://i.postimg.cc/7fCLJmP1/image.png) (https://postimg.cc/7fCLJmP1)
My guess is the IC in question is fake - the BB logo is way off.
Try the alcohol test. Or is it acetone? Im pretty sure its alcohol but if anyone can chime in to verify...
Anyway, dip a q-tip into the alcohol and rub the top of the ic. If the printing comes off its fake.
Quote from: brokenstarguitar on August 31, 2019, 10:37:12 AM
Try the alcohol test. Or is it acetone? Im pretty sure its alcohol but if anyone can chime in to verify...
Anyway, dip a q-tip into the alcohol and rub the top of the ic. If the printing comes off its fake.
Thanks!
Tomorrow i'll try! ;)
Try measuring the offset voltage.
https://www.vintage-radio.net/forum/showthread.php?t=93127
Quote from: brokenstarguitar on August 31, 2019, 10:37:12 AM
Try the alcohol test. Or is it acetone? Im pretty sure its alcohol but if anyone can chime in to verify...
Anyway, dip a q-tip into the alcohol and rub the top of the ic. If the printing comes off its fake.
I'm not sure this is in any way conclusive. I get lots of micro controllers from Microchip Inc. None are fakes since they are direct from the manufacturer. After you've pulled them in and out of the breadboard a few times, the printing on the top starts to wear off, especially if your hands are sweaty. The grease on your fingers is enough. I know other manufacturers who use similar markings that wear quickly, so it's not a one-off.
There are quite a few manufacturers that produce chips with printing that can only be seen if the light is just right. I can't for life of me work out why they should do that when there are others that manage to produce printing that is easily readable - but they can all be easily rubbed off. I don't know how that happens sometimes because I have no reason to touch the tops. It's as though the ink evaporates.
I recently built a Dist+ type pedal and selected an odd 741 that has been in a parts drawer for ages. It is in a very rounded 8pin DIP and only has "741" clearly printed on top. Nowadays, you would suspect a fake, but no - it was probably one of the cheap quality fails that used to turn up in Archer experimenters component packs. It works fine in the circuit.
No notch between pin 1 and 8 and shallow pin 1 indent = Fake:
https://www.stereo.net.au/forums/topic/289098-fake-opa2134s/
Quote from: Rob Strand on September 01, 2019, 05:34:04 AM
No notch between pin 1 and 8 and shallow pin 1 indent = Fake:
https://www.stereo.net.au/forums/topic/289098-fake-opa2134s/?tab=comments#comment-4355128
I wonder how "Alan R" makes that conclusion. If true, then my 2134 shown above is fake. I got it from Tayda - do we know whether or not Tayda sells fakes? There can be more than one plant (fab) that a manufacturer uses for any particular IC (TI has fabs throughout the world), so it is possible that the same IC from the same manufacturer might be found with physical differences.
QuoteI wonder how "Alan R" makes that conclusion. If true, then my 2134 shown above is fake. I got it from Tayda - do we know whether or not Tayda sells fakes? There can be more than one plant (fab) that a manufacturer uses for any particular IC (TI has fabs throughout the world), so it is possible that the same IC from the same manufacturer might be found with physical differences.
Hard to know. It would be nice to find something from TI.
This TI thread, with even dodgier looking parts, got fobbed off,
https://e2e.ti.com/support/amplifiers/f/14/t/534233
and the dead link isn't of much use either,
https://web.archive.org/web/20170421145615/https://e2e.ti.com/group/helpcentral/f/301/t/113197
I suppose that teaching people how to spot fakes would also teach the counterfeiters how to make better fakes.
That broken link is https://e2e.ti.com/administrators1/helpcentral/f/301/t/113197.
Quote from: anotherjim on September 01, 2019, 12:46:48 PM
I suppose that teaching people how to spot fakes would also teach the counterfeiters how to make better fakes.
I agree. Also, the semiconductor business is highly competitive, so adding cost to a product by making it counterfeit resistant might be detrimental. As with just about anything, if you want to be sure of what it is, buy it from someone you're sure of. That goes for "independent distributors" as well as end consumers.
QuoteI suppose that teaching people how to spot fakes would also teach the counterfeiters how to make better fakes.
I suspect one reason some of the fakes look fake is because of the limitations of the printing machines. That would boil down to how much money the fakers want to invest in their printing equipment. If manufacturers make the print and surface patterns hard to copy and publicized the details it would help. However, it would only stop the small-time outfits. The larger organization would be able to buy top notch equipment. It's the exact same problem with fake money.
At the end of the day people are still buying stuff off of ebay because it's cheap. For medical equipment we have to get certificates of conformance where the seller has to sign something guaranteeing the parts, and those seller demand the same thing from their suppliers. The problem is small dodgy suppliers will sign anything. So it's really boils down to buying from known and trusted suppliers.
Quote from: GGBB on September 01, 2019, 09:20:33 AM
If true, then my 2134 shown above is fake. I got it from Tayda - do we know whether or not Tayda sells fakes?
I've bought 2134s from Tayda in the past. While I couldn't say for sure whether they were genuine or not, they were certainly functional, and not noisy or anything like that.
Quote from: EBK on August 31, 2019, 02:20:19 PM
Try measuring the offset voltage.
https://www.vintage-radio.net/forum/showthread.php?t=93127
Interesting, I'll take a look!
Quote from: Rob Strand on September 01, 2019, 05:34:04 AM
No notch between pin 1 and 8 and shallow pin 1 indent = Fake:
https://www.stereo.net.au/forums/topic/289098-fake-opa2134s/
I tought the same when I received it
Quote from: bluebunny on September 02, 2019, 03:33:34 AM
I've bought 2134s from Tayda in the past. While I couldn't say for sure whether they were genuine or not, they were certainly functional, and not noisy or anything like that.
That's been my experience with the ones I bought as well. I have a-b compared them with TL072 in a couple of circuits and didn't notice any difference, but I'm not sure I should since TL072 is quite decent as well.
what is so special in the Burr Brown opamps?
are they so much better? i never heared the diference between an LM308 and a Ua741, why is it such a big deal?
most schematics seem to work with every opamp and good circuit design is more important than mojo parts anyways.
Quote from: iainpunk on September 06, 2019, 08:54:36 AM
what is so special in the Burr Brown opamps?
are they so much better? i never heared the diference between an LM308 and a Ua741, why is it such a big deal?
most schematics seem to work with every opamp and good circuit design is more important than mojo parts anyways.
I'll provide a somewhat unsatisfying answer.
Sometimes we pick an op amp with better performance characteristics precisely because we want it to impart
less mojo. Depending on the application, we could be after lower noise, higher current capability, better slew rate for high gain circuits, better offset voltage.
Quote from: Rob Strand on September 01, 2019, 05:43:39 PM
At the end of the day people are still buying stuff off of ebay because it's cheap.
<snip>
So it's really boils down to buying from known and trusted suppliers.
I think this hits the nail on the head. If Analog Devices won't sell you the chip on their own site for less than $5, how is some dude on eBay offering it for $2.50? Be afraid, be very afraid!
The 'known and trusted' suppliers all have prices that make sense when compared to manufacturer's own prices. Anyone who doesn't isn't to be trusted.
Of course, for stuff that's out of production, this gets more complicated. At that point, rarity starts to be a big issue and guaranteeing that something is what it claims to be is more difficult. If someone offered me (for example) 50 x SSM2040 chips for a decent price, how would I know they were not fakes? There's no way beyond getting a few and testing them, and then checking that any subsequent chips are the same as those ones.
Quote from: ElectricDruid on September 06, 2019, 05:36:35 PM
If Analog Devices won't sell you the chip on their own site for less than $5, how is some dude on eBay offering it for $2.50? Be afraid, be very afraid!
Great point. TI will sell you the OPA2134 PDIP for $2.05 if you buy 1000 (http://www.ti.com/product/OPA2134/samplebuy). I paid $2.45 for mine from Tayda (6 years ago - I keep old email), and I think they would probably buy in bulk so maybe mine are okay. Do you remember what you paid mickeybellinello?