I'm using a stm32f429Idisc and I'm trying to read via the adc a LM35. I observe that each measure differs from the other up to 5mv. This is a normal behavior or something is configured worng? thanks, Piero

[Hicss.2033]

 I'm sampling at 100 msec and adc is in single mode with PRESC_PCLK_DIV6 and SAMPLE_480CYCLES.

[TDK]

It is normal for ADC values to have some amount of noise. 5mV of noise for 3.3V full scale seems quite reasonable. This means you're getting just over 9 bits of accuracy.

For methods of improving accuracy, read:

https://www.st.com/resource/en/application_note/cd00211314-how-to-get-the-best-adc-accuracy-in-stm32-microcontrollers-stmicroelectronics.pdf

[Hicss.2033]

Thanks. May be that adding an OPAMP may improve the situation