STM8T143 datasheet(36/65 Pages) STMICROELECTRONICS

Part #	STM8T143

Description	Single-channel capacitive sensor for touch and proximity detection

PDF	65 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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36 / 65 page

Design guidelines

STM8T143

36/65

DocID18315 Rev 6

Design guidelines

8.1

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

8.1.1

PCB layout and construction

The PCB traces, wiring, and components associated or in contact with CX 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 CX 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.

STM8T143 Datasheet(PDF) 36 Page - STMicroelectronics