ADC signal noise

[harry123]

Hi, I'm using stm32f429 disc1 adc1 PA4 and GND to get the ADC signal, the voltage of the signal is 300 mV. The signal that I'm getting after conversion has some noise, But the same signal when seen through an oscilloscope has no noise. The noise or distortions are getting generated once I connect to the pins of the powered-on board.

[TDK]

General tips to improve accuracy are here:

https://www.st.com/resource/en/application_note/an2834-how-to-optimize-the-adc-accuracy-in-the-stm32-mcus-stmicroelectronics.pdf

Should generally expect at least a few counts of noise for 12-bit measurements. More for high-impedance signals.

[KDJEM.1 · Accepted solution]

Hello @harry123 ,

It is mentioned in the errata sheet ES0206 that some internal noise may impacting the ADC accuracy and workaround option is suggested.

For more detailed workaround, I advise you to refer to the application note "How to improve ADC accuracy when using STM32F2xx and STM32F4xx microcontrollers"  AN4073.

I hope this help you.

Thank you.

Kaouthar