Dropouts in ADC capture on STM32H743

[ANovi.7]

If I connect a constant rising signal at the ADC input, I observe significant fluctuations at certain ADC values. These fluctuations always appear at the same ADC values. The affected values have the following format XX500, e.g. 18500, 19500, 20500 etc.

I was also able to reproduce this behavior with the NUCLEO-H743ZI and the example projects (ADC_DMA_Transfer and ADC_RegularConversion_Polling) from the current cube firmware V1.5.0. The graphic in the appendix shows a recorded ADC values, which shows the problem.

Can someone help me to solve the problem?

[fbar]

Thanks for sharing! Looks better, but not entirely ok...

[Hh.1607]

ADC clock how many M do you configure?

[ANovi.7]

I am out of the office until 25.11.2019.
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[Hh.1607]

I also encountered this situation, the higher the configuration, the greater the signal impact

[ANovi.7]

I am out of the office until 25.11.2019.
Note: This is an automated response to your message "User15744079967188602917 answered you: Fluctuations in ADC capture on STM32H743" sent on 22.11.2019 8:39:12.
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[ANovi.7]

I have tried different ADC clock configurations. The dropouts will not disappear in this way.

[Hh.1607]

Can you think that the ADC stability of H7 is not as good as that of F4?

[Hh.1607]

F4's ADC is still very stable

[ANovi.7]

I switched from F4 to H7 because F4 ADC had a lot of noise. With the same RC element and 12 bit value, I measured 3x higher noise with F4 than with H7.