31–40 of 141 posts
I still have a huge trauma coming from the ESP32 ADC. Why don't they integrate good ADCs? We are waiting for ages now. Non-linear as hell - and evil side effects once you use the calibration curves.
Err, the title isn't really correct. The genuine part is still only $4. This is a 60 cent knockoff. Not having done design in a while but still having a rough feeling for costs I was a bit confused.
Honestly: no one of the bigger players in the industry pays the prices you see on Digikey/Mouser/Farnell (with the exception maybe for prototyping stuff). Often you have direct delivery contracts with the vendors. That the ADS1115 costs I have access to our internal STM32 pricing. You'd be shocked.
Earlier quoted context omitted.
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.
What does TI do with their out-of-tolerance products? Straight in the garbage?
I still have a huge trauma coming from the ESP32 ADC. Why don't they integrate good ADCs? We are waiting for ages now. Non-linear as hell - and evil side effects once you use the calibration curves.
> Why don't they integrate good ADCs? There are a bunch of reasons but the primary reason is that good ADCs are made using a different mixed signal process than microcontrollers. MCU ADCs are capacitive charge-balancing successive-approximation type which limits their sensitivity and precision. Standalone ADCs also eliminate significant sources of noise like temperature fluctuations and electronic noise (the digital…
Err, the title isn't really correct. The genuine part is still only $4. This is a 60 cent knockoff. Not having done design in a while but still having a rough feeling for costs I was a bit confused.
LCSC is definitely genuine. I'm not sure why people are so surprised that companies like Mouser have insane markups.
Err, the title isn't really correct. The genuine part is still only $4. This is a 60 cent knockoff. Not having done design in a while but still having a rough feeling for costs I was a bit confused.
Honestly: no one of the bigger players in the industry pays the prices you see on Digikey/Mouser/Farnell (with the exception maybe for prototyping stuff). Often you have direct delivery contracts with the vendors. That the ADS1115 costs I have access to our internal STM32 pricing. You'd be shocked.
Earlier quoted context omitted.
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.
Ah oops I missed that. Maybe an ADX111A then?
Analogy: https://datasheet.lcsc.com/lcsc/2302211830_analogysemi-ADX11...
TI: 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/n...
Earlier quoted context omitted.
> Why don't they integrate good ADCs? There are a bunch of reasons but the primary reason is that good ADCs are made using a different mixed signal process than microcontrollers. MCU ADCs are capacitive charge-balancing successive-approximation type which limits their sensitivity and precision. Standalone ADCs also eliminate significant sources of noise like temperature fluctuations and electronic noise (the digital…
Standalone ADCs are often SARADCs as well (and are specified as such.)
I'd like to know more about the world of ADCs. I've used the ADS1115 with success but only at very slow speeds. On the current project we started with an MCP3208 via SPI. It did the job but only has 8 channels and it's slow (100K samples per sec). To get something faster we switched to ADS7953. It has 16 channels and runs 10 times faster. It's somewhat more complex to code, and you can only get the highest sample rat…
I recall reading about a project at CERN to design a 12bit ADC chip that could sample at tens of GHz, maybe 50 or more.
I was perplexed at how they could achieve this.
Turned out it was the same we programmers do. Parallel processing.
They had taken a 12bit SAR unit which ran at like MHz rates, and just cloned it many times. They then had a large analog multiplexer in front to route the signal to the active ADC unit in a round-robin fashion.
That takes a lot of chip real-estate, and the analog muxer had to be carefully designed.
For a simpler approach to speed there is Flash ADCs[1], which kinda brute-force it.
For precision I know multi-slope ADCs[2] are often used.
Sadly I don't know much about the history, and would also love to learn more about it. Bound to be some fascinating stories there.
[1]: https://en.wikipedia.org/wiki/Flash_ADC
[2]: https://www.analog.com/media/en/training-seminars/tutorials/...
Has there been any updates on ADC technology? What does SKA/CERN use?
And if you want to see CERN's multimeter, check this out.
Marco Reps is a treasure.