DocID15067 Rev 3 21/49
AN2834 ADC errors
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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 introd
uces 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).
Figure 18. Crosstalk between I/O pins
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 19.).
Figure 19. EMI sources
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