4 ms·

> 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 hobbyi

> 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.

q3k 1y ago
Interesting, most of the counterfeits that affect me (eg. FTDI, STM32 clones) have been just straight up clones developed from scratch, not excess inventory / ghost shifts / packaged rejects. I guess it might be a digital/mixed-signal split, with the two worlds having different issues? (also interestingly the STM32 clones I've seen had stacked die flash because they didn't fab them in a technology that could also do flash, so you can easily tell the counterfeit from sanding down the package and looking for an extra set of bonding wires; it's also a cool place to access the internal flash bus if you wanna bypass some readout protection :) )
- throwup238 1y ago
  I remember the mess with FTDI clones back when I was still a hobbyist and buying stuff from eBay, but ever since I’ve started doing EE professionally I rarely run into anything that bad. You’re not going to make a clone Marvell processor for example, but I’ve run into several ghost shift runs from a distributor. I don’t usually buy from electronics markets in Shenzhen either so that probably helps.
  - londons_explore 1y ago
    Buy in bulk from the Shenzhen markets and sellers will be pretty clear that you're getting a clone, and will give you samples of that specific clone so you can QA your product with them. (Some popular devices have multiple clone suppliers). I now always buy clones where possible - whilst not all features are implemented and some specifications won't be met, the devices seem to match the original for reliability, and sometimes even come with their own cloned modded datasheet.
jamesbowman 1y ago
Author here. I did consider this, as others have reported getting ADS1015 marked as ADS1115. If it were an ADS1015 the readout would be truncated at 12 bits. These parts definitely delivered 16 bits of readout.
- hex4def6 1y ago
  I worry about the demo boards being radically different in terms of layout etc. Even if you're using the same interface and power supply, the PCB may be affecting performance. Getting full spec performance out of an ADC requires having good layout power supply routing etc. I would transplant the chips from PCB A to PCB B and vice versa. See if the performance follows the chip or the PCB. Also check power consumption before / after board swaps. If they are fakes, that would be significantly different.
  - londons_explore 1y ago
    It doesn't take much crosstalk from some clock signal into the signal you're measuring to really mess stuff up... Many of these Dev boards are not produced with as much care or knowledge as the chip design itself.
- throwup238 1y ago
  Ah oops I missed that. Maybe an ADX111A then?
  - gsmecher 1y ago
    Oh my - good find, and also, eek. Analogy: https://datasheet.lcsc.com/lcsc/2302211830_analogysemi-ADX111AQFN10_C5359372.pdf https://datasheet.lcsc.com/lcsc/2302211830_analogysemi-ADX11... TI: https://www.ti.com/lit/ds/symlink/ads1115.pdf https://www.ti.com/lit/ds/symlink/ads1115.pdf Analogy's datasheet is directly cribbed from TI's (see TI Fig. 7-7 / Analogy Fig. 22½, pg. 18). This already passes my "run away screaming" threshold for trust, but a decapping would help me understand whether they've stolen the physical design (bad) or just cloned it (bad). See also: https://community.element14.com/members-area/f/forum/53365/new-clone-on-the-block https://community.element14.com/members-area/f/forum/53365/n...
deleted 1y ago
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q3k 1y ago

Interesting, most of the counterfeits that affect me (eg. FTDI, STM32 clones) have been just straight up clones developed from scratch, not excess inventory / ghost shifts / packaged rejects. I guess it might be a digital/mixed-signal split, with the two worlds having different issues? (also interestingly the STM32 clones I've seen had stacked die flash because they didn't fab them in a technology that could also do flash, so you can easily tell the counterfeit from sanding down the package and looking for an extra set of bonding wires; it's also a cool place to access the internal flash bus if you wanna bypass some readout protection :) )

throwup238 1y ago
I remember the mess with FTDI clones back when I was still a hobbyist and buying stuff from eBay, but ever since I’ve started doing EE professionally I rarely run into anything that bad. You’re not going to make a clone Marvell processor for example, but I’ve run into several ghost shift runs from a distributor. I don’t usually buy from electronics markets in Shenzhen either so that probably helps.
- londons_explore 1y ago
  Buy in bulk from the Shenzhen markets and sellers will be pretty clear that you're getting a clone, and will give you samples of that specific clone so you can QA your product with them. (Some popular devices have multiple clone suppliers). I now always buy clones where possible - whilst not all features are implemented and some specifications won't be met, the devices seem to match the original for reliability, and sometimes even come with their own cloned modded datasheet.

jamesbowman 1y ago

Author here. I did consider this, as others have reported getting ADS1015 marked as ADS1115. If it were an ADS1015 the readout would be truncated at 12 bits. These parts definitely delivered 16 bits of readout.

hex4def6 1y ago
I worry about the demo boards being radically different in terms of layout etc. Even if you're using the same interface and power supply, the PCB may be affecting performance. Getting full spec performance out of an ADC requires having good layout power supply routing etc. I would transplant the chips from PCB A to PCB B and vice versa. See if the performance follows the chip or the PCB. Also check power consumption before / after board swaps. If they are fakes, that would be significantly different.
- londons_explore 1y ago
  It doesn't take much crosstalk from some clock signal into the signal you're measuring to really mess stuff up... Many of these Dev boards are not produced with as much care or knowledge as the chip design itself.
throwup238 1y ago
Ah oops I missed that. Maybe an ADX111A then?
- gsmecher 1y ago
  Oh my - good find, and also, eek. Analogy: https://datasheet.lcsc.com/lcsc/2302211830_analogysemi-ADX111AQFN10_C5359372.pdf https://datasheet.lcsc.com/lcsc/2302211830_analogysemi-ADX11... TI: https://www.ti.com/lit/ds/symlink/ads1115.pdf https://www.ti.com/lit/ds/symlink/ads1115.pdf Analogy's datasheet is directly cribbed from TI's (see TI Fig. 7-7 / Analogy Fig. 22½, pg. 18). This already passes my "run away screaming" threshold for trust, but a decapping would help me understand whether they've stolen the physical design (bad) or just cloned it (bad). See also: https://community.element14.com/members-area/f/forum/53365/new-clone-on-the-block https://community.element14.com/members-area/f/forum/53365/n...

deleted 1y ago

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