I/O Pin Crosstalk; Emi-Induced Noise; Figure 18. Crosstalk Between I/O Pins; Figure 19. Emi Sources - ST STM32 Application Note

AN2834
2.2.10

I/O pin crosstalk

Switching the I/Os may induce some noise in the analog input of the ADC due to capacitive
coupling between I/Os. Crosstalk may be introduced by PCB tracks that run close to each
other or that cross each other.
Internally switching digital signals and I/Os introduces high-frequency noise. Switching high-
sink I/Os may induce some voltage dips in the power supply caused by current surges. A
digital track that crosses an analog input track on the PCB may affect the analog signal (see
Figure 18).
1. Case 1: Digital and analog signal tracks that pass close to each other.
2. Case 2: Digital and analog signal tracks that cross each other on a different PCB side.
2.2.11

EMI-induced noise

Electromagnetic emissions from neighboring circuits may introduce high-frequency noise in
an analog signal because the PCB tracks may act like an antenna (See

Figure 18. Crosstalk between I/O pins

Figure 19. EMI sources

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ADC errors
Figure 19.).
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