Q
What's the difference between the INL spec and the noise spec on the ADC?
A
Any given ADC conversion result has both an INL error and a noise error. The
INL specification is
15ppm of FSR max (i.e. the INL error at any given code is accurate to at least
16 bits). Depending
on the range and the update rate this ADC conversion result will have a varying
amount of noise
on it.
The noise which exists on this ADC conversion result is random and is equally
as likely to be
positive as negative. Hence by doing more averaging this noise error can be
reduced. Since the
INL will stay constant for every ADC conversion (given the same DC input) then
software
averaging will not remove the INL error.