Hi everyone,
I have a nrf52-DK, I made samples with the saadc unit and i noticed there are unexplained peaks. I connected the MIC's output (its VDD is from the board) to an oscilloscope and saw the peaks occurs when the vdd(provided from a usb cable) has minor fallings.
The circuit is in the picture below:
Here the green graph is Vdd, and is measured 2.97[V], the yellow graph is the microphone's output.
I then connected the MIC to a power generator and with the same input voltage the signal was clear.
When i made the coin battary to power the board the voltages in the scope had bigger falldowns, and the MIC's output is worse:
and after a few second suddenly everything clears out and everything is good:
Why from a usb it doesn't happen? What can cause this problem?
Thank you!
