S-TouchTM Capacitive Touch Controller PCB Layout Guide 2

The blank area can be filled with grounding copper foil (trace width of 6 mil, grid size of 30 mil).

The top layer can be used to lay ordinary signal traces (excluding sensor signal traces). Sensor signal traces should be laid out at the bottom layer as much as possible.

The distance between the sensing electrode and the grounding copper foil should be at least 0.75 millimeters.  diode

Second layer (bottom layer)

The S-TouchTM controller and other passive components should be designed and laid out at the bottom level.

The sensor signal traces will be laid out at the bottom layer. Do not lay the sensor signal trace of one channel under the sensing electrode of other sensing channels.

Figure 3: Wiring method of sensor signal traces under the touch pad

The blank area can be filled with grounding copper foil (trace width of 6 mil, grid size of 30 mil).

The distance between the sensor signal trace and the grounding copper foil should be at least twice the width of the sensor signal trace. diode

To reduce crosstalk, the distance between the two sensing electrodes/sensing signal traces should be increased as much as possible. If possible, add a grounding copper foil between the two sensing electrodes/sensing signal traces.

The length of sensor signal traces does not need to be completely equal. By using matching tuning capacitors, it is possible to achieve balance in the input capacitance between the two channels. However, when PCB space allows, it is best to use sensor signal traces of equal length (the size of sensor electrodes is also uniform). In this way, in order to adjust the sensor capacitance values of all sensing channels to within the dynamic range sensed by the controller, only one standard reference capacitor needs to be set, simplifying the design difficulty.

Any clock, data, or periodic signal trace should not be laid adjacent to or parallel to the signal trace of the sensor. These signal lines should be as perpendicular as possible to the signal traces of the sensors, or arranged in other areas of the PCB. diode