Recommended resistor and power ratings for STM32F105 ADC

[ax369]

We are using STM32F105 ADC function in some of our products for temperature sensing, etc. We found that sometimes it has accuracy issue after operating for a while. We suspect that it's the power, resistor, or capacitor we used are not of good enough ratings. Would you please shed some lights on what are the recommended ratings(accuracy, temperature, etc) for these components to get consistent accurate results for these applications? 

Attached is the diagram of one example. Please let me know if it should be revised.

[Peter BENSCH]

Welcome @ax369, to the community!

With resistors and capacitors, mainly only the tolerance plays a role, otherwise the measurement accuracy depends more on the source impedance and the settings of the ADC. You can find valuable tips in AN2834: How to get the best ADC accuracy in STM32 microcontrollers.

• What are you connecting to REAR-TEMP?
• What are the settings of the ADC channel?

Regards
/Peter