AN3960

Conclusion

Doc ID 022082 Rev 1

19/21

5

Conclusion

Among the techniques to protect electronic systems against ESD stress, the cheapest and

simplest method is to add a small serial resistor of about 50

Ω. For greater robustness a

diode or an ESD protection device can be added.The drawbacks of these choices are price,

leakage, and input capacitance. In an environment where ESD can strike frequently, the

most effective way is to use a combination of the techniques described in Section 3:

Protecting against ESD, for example, by simultaneously using a spark gap (with a 10 k

Ω

serial resistor), a ground ring and robust firmware. In any touch sensing domain, most of the

protection is provided by a dielectric overlay which is nearly always used. However, an ESD

stress can strike from anywhere so, other methods are recommended in parrallel with a

dielectric overlay.