Avoidance of ESD effects

The problem of avoiding electrostatic discharge (ESD) in electronic circuits is addressed. The best design approach for ESD is no current discharges for direct ESD events and a cost-effective internal shield for indirect ESD events. It is shown that there can be a conflict between emission and ESD designs. When ESD current flows, the current is always common-mode current. Even the correct model for the resistance of the arc discharge is dependent on the rate of closure between the intruder and the reception. Because of this, protection could range from inadequate to overdesign with present-day test generators. The fields near the arc discharge path are predominantly magnetic and some useful relationships are given. Radiation pickup depends on surface impedance, slot openings and separation distance between the arc and the sensitive circuit(s)