I want to use the "temperature sensor" feature of the ADC.
I use Kinetis K22F Sub-Family processor, for which the temperature slope is (Typ.) 1.62 mV/C and the ADC resolution is 16bit.
I read carefully AN3031 and the post about the slope calculations here and SW implementation wasn't a problem.
My MCU Vcc is powered by 3.0V +-3% via LDO.
1. For a reason I don't understand, any minor change in Vcc result with a major temperature error:
Shouldn't the 3% error be negligible if ADC proportional to 1/Vcc :
Delta_ADC = a/100 - a/103 = a*3/10000
2. Is there a way to use another reference (i.e. VREF) for the temperature sensor?