How to compensate the adc value when temperature change

Hi Erik!

You do not say anything about your hardware. Here is an example for the MSP430G2553's ADC10 by using the calibrated values that are stored in the TLV:

Dennis

Assuming that you use internal temperature sensor, internal reference and internal ADC: You shall gather/measure reference voltage calibration data at whole temperature range. Usually 3..4 calibration points is good enough for most applicaitons and references. Such calibration data will compensate for temperature sensor and ADC errors, and what's most important - voltage reference thermal drift. So in your application you periodically measure temperature, calculate actual voltage of the reference (using calibration data /w interpolation) and then calculate ADC result which will be temperature-compensated.

Optionally you can use factory-calibration values as Dennis suggested