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

[Hari]

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

[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

[Hari · Accepted solution]

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