Two-point Calibration

To make the temperature measurements as accurate as possible, two calibration points are needed. The first calibration point, ADCT1, is the output from the ADCT2 at the first calibration temperature, T1. This application note uses room temperature (25°C) as this first calibration temperature. The second calibration point, ADCT2, is the output at the second calibration temperature, T2. The second temperature should be chosen a little higher than the temperature range of interest. The output from the ADC is given in LSBs or K, so the calibration values ADCT1 and ADCT2 have to be converted to °C. This is done by subtracting 273 from the values.