Hi! I use embendded ADC1 channel 3 in STM32H743VIT6 for sampling data. Input in differential mode. For improve SNR i added capacitor 47pF parallel to diff input pins see fig1.
Also this capacitor required by AN5354
This led to decrease noise floor level, but its produces many spurs see fig below.
If i remove this capacitor (47pF) spectr became look very good see
Please help me to understand how this capacitor impact to input driver and produce nonlinear products?
Thanks a lot!
