October 2011

Doc ID 022082 Rev 1

1/21

AN3960

Application note

ESD considerations for touch sensing applications

Introduction

Electrostatic discharge (ESD) is not a new phenomenon. It is often used to describe high

voltage that may produce permanent damage. ESD can be destructive and may leave a

sytem in an unknown state from which recovery is impossible. Fortunately, it can be

prevented by several methods. Some of these methods are cheap whilst some modify the

behavior of the equipment. The ideal situation is to balance both of these factors to obtain a

robust application which is not too expensive and which is unlikely to behave erratically.

This document describes ESD, its causes and risks. Several models and standards relating

to ESD simulation are outlined. Typical ESD protection techniques are explained. Test

results are presented for the STM8T142-EVAL evaluation board which was tested against

ESD events using some of the protection methods detailed in this application note.

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