STM8T143AU62TTR Datasheet, PDF (36/65 Pages) STMicroelectronics – Single-channel capacitive sensor for touch and proximity detection

Design guidelines
8
Design guidelines
STM8T143
8.1
8.1.1
Sensitivity adjustment
Several factors impact device sensitivity:
• The sensing electrode material and size
• The touch panel material and thickness
• The board layout and in particular the sensing signal tracks
• The ground coupling of the object (finger or hand) and sensor
• The touch or proximity detection threshold selected
PCB layout and construction
The PCB traces, wiring, and components associated or in contact with C_X pins become
touch sensitive and should be treated with caution to limit the touch area to the desired
location.
Even with AET it is important to limit the amount of stray capacitance on the C_X pin. This can
be done by minimizing trace lengths and widths. To minimize cross-coupling, tracks from
adjacent sensing channel should not run close to each other for long distances. For detailed
information, refer to application note AN2869.
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