EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: 1001 on December 05, 2024, 08:26:16 pm
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I bought these current feedback amplifiers on aliexp for about 3 euros, from the x-ray they seem to have the pins connected to the die as in the datasheet.
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from the texas instriment evaluation board the silkscreen appears different, could they be fakes?
if that were the case it would be strange, I don't think it would be worth rebranding similar chips or building fake ones from scratch.
I know of only one other chip with the same case and the same pins connected to the die, the TPA6120A2
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I have never seen TI use that font, so that would scream fake to me.
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Fakes with different batch numbers for each IC? I don't think so.
They're just unsoldered ICs.
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Their surface is very obviously painted and marking is extremely dodgy as well.
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Fakes with different batch numbers for each IC? I don't think so.
They're just unsoldered ICs.
Regardless of what's inside the IC, their marking is 100% fake. Best case they're relabeled salvaged IC, worst case something entirely different.
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Fakes with different batch numbers for each IC? I don't think so.
They're just unsoldered ICs.
It would be very trivial to make the laser marking machine put a different number on each part.
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It would be very trivial to make the laser marking machine put a different number on each part.
Blacktopped ICs usually look as good as new and the same batch number is used on all circuits so as not to arouse buyers' suspicions.
I've never seen such rotten ICs blacktopped.
The top of the ICs should be scraped to see if any paint is peeling off.
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^You should use solvent, not scrape.
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after visual and x-ray examination i could test quiescent current of each opamp (12-15mA) and bandwidth with voltage gain of 100,
or do you suggest a better test?
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The printing is 100% fake, still might be recovered chips. The first chip has a different dot, that's not looking good.
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I constantly buy components with fake markings on Aliexpress, for MOSFET the defect rate is 1 out of 40, for microcircuits 1 out of 8 (no more).
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I tested the bandwidth with a voltage gain of 100 (40dB) and at 20Mhz the opamp holds about 33dB.
is it too out of spec? What do you think?
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I tested the chip with a different dot, same results. at this point I think they are original chips, maybe used.
I also noticed in a photo found on the xDevs.com site some TI chips with the same font in the marking, it is the board of an HP 53131.