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Hello Eveybody ! 


I would like to know if anyone has carried out any tests with the internal temperature sensor of the DSPIC33CK256MP508 and perhaps has some more accurate data than mine.
Given that I have found very little information online, nor from Microchip, I have based my calculations on the value stated in the datasheet, a typical 'TCOEFF' of 1.5 mV/°C, which, of course, can vary from chip to chip.
I don't dare to question the accuracy of the procedure I followed, but it might be useful to share the experience.
I limited myself to a single-point calibration by reading the temperature at the centre of the TQFP-80 package with a thermocouple, obtaining a correspondence of 36.7 °C -->957 from the ADC (AN24).
The datasheet only provides the junction-to-ambient thermal resistance of the TQFP-80 (simulated) as θJA: 50.67 °C/W. Microchip estimates the thermal resistance θCA of the same package to be approximately 24.4 °C/W, but this depends on various factors. Based on the operating conditions of the MCU, I have assumed a consumption of 180 mW.
The available data are:

T_amb_cal=27.7 °C
ADC_Cal= 957
T_package=36.7 °C 
P_consumption=0.18 W
Theta_JA=50.67 °C/W
Vref: 3.3 V 

The extrapolation for the internal temperature is:

Temperature_CPU = (1000 * Temp_CPU - 888510) / 1860 , with Temp_CPU equal to the reading of AN24.