1 Reply Latest reply on Aug 20, 2019 5:23 AM by AH_96

    Mutual vs Self Capacitance


      Hey all,

      I'm new to the whole CapSense Topic,

      but I want to develop with a PSoC 4 a Touchpad, which should be resistant to  interferences (also high frequency interferences), but also senses a touch reliable.

      I also want to recognize gestures (also 2-finger gestures like zoom).

      I know that I can use the CSD-Sensing method with 5x5 centroid Setting and CSX-Sensing method for two finger operations.

      But I'm not sure which is the best to work with if  high frequency devices are nearby. Is any of the Methods (CSX or CSD) more reliable towards high frequency interferences?

      And are there any documents which describe very detailed why the one method is higher rated than the other?


      Thanks in advance


        • 1. Re: Mutual vs Self Capacitance

          Hello leko_4405711


          CSX and CSD perform in a similar way with respect to radiated noise. CSX is more prone to conducted noise since the noise from the VDD line (power supply) is directly coupled onto the Tx line.


          If the parasitic capacitance of the sensors are high (due to large sensor dimensions), CSX method is preferable.


          Therefore, the choice between CSX or CSD must be made based on the application and the requirement.


          Thanks and regards