[sdiy] CV input op-amp circuit

Mike Beauchamp list at mikebeauchamp.com
Sat Dec 5 22:42:29 CET 2020

On 12/5/20 4:01 PM, Brian Willoughby wrote:
> Even with all of that potential complexity taken care of, there's still the possibility that hitting a chip with all it can take will affect sensitive peripherals like the ADC. Personally, I prefer off-chip ADC, even going to the extent of placing the stand-alone ADC chip near the signals being read - such as pots and faders - so that ground and voltage references are more controlled than they might be near a digital processor switching at tens or hundreds of megaHertz.
> Brian

That sounds very smart Brian. I've had good luck using the internal ADC 
on some Teensy 3.2's but only when averaging many samples, etc.

Regarding protecting ADC inputs, is anyone using external BAT54S 
schottkey diodes? It seems like it might be easier to slap these in 
rather than rely on the internal uC's diodes and the issues youve raised 
of sharing that current if multiple pins are overloaded etc.


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