Fastest ADC in the Arduino World

[ats3788]

Hello
What is the fastest ADC in the Arduino World ?
I fiddle with the ADS1115 and MCP3421 but it would be nice to fiddle with a faster Controller.

[Kleinstein]

If it is just about fast the µC internal ADCs are aready quite a bit faster, but lower resolution. With the AVR based one this should be some 16 kSPS at 10 bits and maybe 8 bit performance up to some 70 ksps.
With the Arduino typical overhead this is about as fast as the SW side can do much with the result.

It gets quite a bit faster with ARM based Arduino versions: they may offer 12 bits up to some 2 or 5 MSPS depending on the chip used.

[dobsonr741]

Why do you need a faster converter? Consider what you’ll be doing with the volume of data a faster ADC dumps at you.

[MasterT]

My recent finding is nucleo-G474re (form factor arduino and could be programmed under arduino IDE):
11.2 MSPS when adc overclocked. Thare are 5 internal adc, so theoreticallly 56 MSPS.
It's only uCPU in stm32 world that have adc with such high speed, others usually can't be drivven above specified ~5 MSPS, even 480 MHz core H7 series.

[ats3788]

Why Why Why, because we are Hobby tinkerer and I would like to sample a 50Hz Wave properly The ADS1115 with its ADS1115_860_SPS is almost OK. 2k SPS would be perfect faster even better. Faster then 2K is not necessary.
Thank you for the answers anyway.

[iMo]

You have to look for an SPI ADC with 16bit resolution (as your 1115 is 16bit, mind its ENOB at 860Sampl/sec is lower), and the required sampling rate.
For example I have an SAR MAX11166/67 in my junkbox gathering dust for ages, those are 16bit, SPI, max 250/500K Sampl/sec with true bipolar inputs (+/-5V max).
There are tons of other ADCs with such params available (except they are usually not with true bipolar inputs).

PS: also mind many sigma delta ADCs have got a notch filter at 50/60Hz, no idea how it may interfere with your intention to measure 50Hz signal, however..

[Kleinstein]

The 50/60 Hz notch with SD ADC is only present with the slower conversion rates, like 50 SPS and less. They include a digital low pass filter by design as part of the ADC function and with the low conversion rates it helps to suppress main hum to have a zero at the mains frequency. Of cause this no longer works with faster conversions.

For the speed / bandwidth the difference between SD ADCs and SAR types (e.g. the usual µC inernal ones) may be relevant:
The SD ADCs are averaging over some time and doing low pass filtering. They don't need much extra AA filtering.
With SAR ADCs the input sampled for a rather short time and one can thus get aliasing from higher frequencies. If a classic AA filter is used the usable BW will be lower than the Nyquist limit and usually the BW a SD ADC can use at the same sampling rate. If no AA filtering is used, one will also get parts from higher frequencies - this may be bad (extra noise from aliasing) or good e.g. with subsampling to include higher frequencies in RMS readings.

[MarkT]

I've interfaced to an ADS8885 on the Teensy 4.0.  That chip is an SAR ADC, 18 bit, upto 400kSPS.

[ats3788]

Thank, you very much  iMo and Kleinstein, MarkT sound good. Check it out

[ats3788]

ok, I admit defeat, the esp32 has a sampling rate that is fast and reasonably accurate Thank you Forum