[sdiy] CV input op-amp circuit

[Ingo Debus]

> Am 07.12.2020 um 05:56 schrieb Brian Willoughby <brianw at audiobanshee.com>:
> 
> All 24-bit ADC chips use delta-sigma conversion, which makes it impossible to place an analog multiplexer in front of the ADC to expand the channel count. Since ∆Σ functions on the difference between each sample, you can't swap in an unrelated channel without getting erroneous conversions.

Sure about that? I have used a 16 bit Delta-Sigma ADC with an analog multiplexer in front of it. Worked great.
Of course the multiplexer does not switch with every new sample for the Delta-Sigma algorithm (this would be way too fast).

> ADC chips that have built-in multiplexers and/or are compatible with external multiplexers are limited to 8-bit, 10-bit, 12-bit, or 16-bit at the most. I don't think I've seen anything with more than 16 bits of accuracy, and far more often 12 bits is a practical limit.

Look here:
https://www.ti.com/product/ADS122C04
24 bits, Delta-Sigma, multiplexer built in.

Ingo