I want to measure temperature of an oven using a thermocouple. The maximum change in the temperature will be 1oC/s. The amplifier section will already contain a low pass filter, but I want to put an extra passive RC filter very close to the ADC input pin of PIC32MX270F256B. However, I can't decide a suitable resistance value (R) because I can't find the input impedance of the ADC pin neither in the datasheet nor in the family reference manual. What range of resistance value can I use here?
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Best Answer
The Reference Manual seems pretty clear on the subject:
The Datasheet gives a recommended input impedance for the ADC: