Question: What is the effect of Prescaler on sensitivity and SNR for a CapSense CSD Application ?
When Prescalar with PSR8 bit is used, the switching frequency is reduced compared to PRS16 bit.
1) This allows to measure higher parasitic capacitance.
2) This can also be useful while using higher resistive materials like Flex PCB, ITO etc. which needs higher charging time.
3) Very high prescaler will reduce the sensitivity.
4) Optimum prescaler value ( where sensors get fully charged and discharged ) reduces the noise, increasing the SNR.