What are the key points when designing RTD or TC circuit?
1. Very high Input impedance and low bias current are two basic requirements to
the signal conditioning circuit processing the micro signal from TC and RTC.
2. 50/60Hz noise needs to be filtered out by signal conditioning circuit or AD
The ∑-Δ ADC would be first choice when the sampling rate is not too high.
3. Every component through the signal path needs to be ultra-low leakage
especially for RTD measurement.
4. Pay attention to the self-heating of RTD and CJC of thermocouple.