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How bad can a $2.97 ADC be?

excamera.substack.com

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Re: How bad can a $2.97 ADC be?

#2

Post by q3k »

Should be easy to compare - sand down both the cheapo and a legit one (with a similar datecode) with fine sandpaper, clean with isoprop and shove under an optical microscope - you can then tell how similar/dissimilar the dies are, you don't even have to look for markings or anything super legible, or even sand them to the same metal layer.

Clones tend to be vastly different - different technology node, architecture, die size, etc. - that's because they are generally functional clones, not mask clones.

(also, as a general shoutout to the low tech sandpaper technique for exploratory work, here's a sanded down RP2350 thrown under a clapped out SEM: https://object.ceph-eu.hswaw.net/q3k-personal/484e7b33dbdbd9... https://object.ceph-eu.hswaw.net/q3k-personal/3290eef9b6b9ad... )

Re: How bad can a $2.97 ADC be?

#3

Post by cheschire »

q3k wrote: post #2

Should be easy to compare - sand down both the cheapo and a legit one (with a similar datecode) with fine sandpaper, clean with isoprop and shove under an optical microscope - you can then tell how similar/dissimilar the dies are, you don't even have to look for markings or anything super legible, or even sand them to the same metal layer. Clones tend to be vastly different - different technology node, architecture,…

It may not even be a clone. As the author said, it could just as easily be production line items that were tested and found to be outside of spec tolerances and resold off-label.

Re: How bad can a $2.97 ADC be?

#5

Post by q3k »

cheschire wrote: post #3
q3k wrote: post #2

Should be easy to compare - sand down both the cheapo and a legit one (with a similar datecode) with fine sandpaper, clean with isoprop and shove under an optical microscope - you can then tell how similar/dissimilar the dies are, you don't even have to look for markings or anything super legible, or even sand them to the same metal layer. Clones tend to be vastly different - different technology node, architecture,…

It may not even be a clone. As the author said, it could just as easily be production line items that were tested and found to be outside of spec tolerances and resold off-label.

Well, that's the point of the experiment, to figure out if it's a clone or a reject :).

Re: How bad can a $2.97 ADC be?

#7

Post by throwup238 »

> So what’s going on with the cheap parts? My best guess is that these are either quite good copies, or failed parts that somehow made their way into the hobbyist supply chain.

The vast majority of counterfeit chips I've seen were from ghost shifts but IIRC TI fabs all their analog parts in house, I doubt they're ghost shift parts or failed QC.

I think its probably a relabeled ADS1015.

Re: How bad can a $2.97 ADC be?

#9

Post by throwup238 »

cheschire wrote: post #3
q3k wrote: post #2

Should be easy to compare - sand down both the cheapo and a legit one (with a similar datecode) with fine sandpaper, clean with isoprop and shove under an optical microscope - you can then tell how similar/dissimilar the dies are, you don't even have to look for markings or anything super legible, or even sand them to the same metal layer. Clones tend to be vastly different - different technology node, architecture,…

It may not even be a clone. As the author said, it could just as easily be production line items that were tested and found to be outside of spec tolerances and resold off-label.

TI makes all their analog stuff in house so that's unlikely. That's far more common for fabless companies that send their parts off to an outside fab.
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