AN4312 datasheet(33/36 Pages) STMICROELECTRONICS

Part #	AN4312

Description	Guidelines for designing touch sensing applications with surface sensors

PDF	36 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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33 / 36 page

DocID024815 Rev 1

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AN4312

Surface sensor design

Figure 28. Ground plane example

Hatched ground plane

Here are some guidelines for satisfactorily designing an application with a hatched ground

plane (see Figure 29):

•

The signal track should cross the ground lines as little as possible

•

The signal track should never follow the ground lines

Figure 29. Hatched ground and signal tracks

3.5.7

Rotary and linear sensor recommendations

Given that the sensitivity must be very high in order to be able to detect the position most

accurately, neither the power plane nor any application signal should run under a rotary or

linear sensor.

MS18981V2

GPIO1

Tkey1

Tkey2

Tkey4

Tkey3

GPIO2

GPIO3

GPIO4

Hatched ground plane (optional)

Flood ground plane (mandatory)

MS18982V1

Must be avoided

Track is OK

AN4312 Datasheet(PDF) 33 Page - STMicroelectronics