3 Replies Latest reply on Jul 15, 2019 10:20 PM by AH_96

    CapSense vias on ground fill

    GrWa_2302706

      Hi

       

      I see the picture from PSoC 4 CapSense Design Guide. It seems putting many vias on the ground plane. May I know what's the function of that? Is it necessary ? Thanks.

       

      BR

      Grace

      CapSense_Ground.PNG

        • 1. Re: CapSense vias on ground fill
          AH_96

          Hi GrWa_2302706

           

          For a CapSense design, it is recommended to route the sensor traces on the opposite side of the sensor layer. This is done to prevent any false triggers of the sensors by accidental finger touch on the sensor. Touching the sensor trace will also lead to increased capacitance as seen by the pin of the IC and this might be registered as a touch of the button.

           

          Hence, the CapSense sensor traces are routed on the opposite layer and connected to the sensor using vias.

           

          Thanks and regards
          Harigovind

          • 2. Re: CapSense vias on ground fill
            GrWa_2302706

            Hi Harigovind

             

            Are the dots I circled in the below picture vias ? If so, I actually wanna know those functions. Thanks.

             

            BR

            Grace

             

            InkedCapSense_Ground_LI.jpg

            • 3. Re: CapSense vias on ground fill
              AH_96

              Hi GrWa_2302706

               

              These are vias and it is called ground stitching. Stitching ground at different points will result in reduction of impedance formed by the traces, thereby, obtaining uniform ground potential throughout the layout.

               

              Thanks and regards

              Harigovind

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