TSENS MPC5675K

[laurayindra]

We are seeing a processor temperature on the TSENS of the MPC5675K that is consistently +10 deg C above the temperature read on the thermal scan.  Why is that?

One point about our design is that the ADC reference voltage is 5 V instead of 3.3.

We expect a 12-bit resolution, so I'm masking off the most significant 4 bits of the calibration values.

[wittkop]

David,

I am working with Laura on the MPC5675K temperature sensor issue.  We are consistently seeing the calculated value of the sensor to be +18 to +20 degrees C above the case temperature.  This is outside the specified +/-10 C tolerance.

What is the recommended method to account for the 5 vdc reference in the TSENS calculation?

[davidtosenovjan]

I have been confirmed that ADC reference does not affect accuracy of temperature sensor. Even though it is a bit different it should be still in specified tolerance +/-10°C. Note that this sensor is relatively imprecise.

[davidtosenovjan]

I have just tried it (with MPC5643L but it should be the same) and I can also see mentioned temperature shift in case 5V is used instead of 3.3V. I am investigating details, letting you know then…