The requirements of IEC61000-4-2 will introduce as followings:
The static to damage electronic devices is a problem not easy to resolve. Once the electronic devices are damaged by ESD, it will usually appear abnormal situations, for example, the function is out of order suddenly. If it’s not a serious problem, it needs to reset for equipment. If it’s a serious damage, the products will be broken. To ensure the functions of electronic products, the international manufacturers always request the products which must comply with IEC61000-4-2 ESD requirements. However, if the electronic product needs the ability of static protection, it’s not only for protection of semi-conductors components, but also in design protection of product system. That will have a full protection against static.
Typical Waveform of Output Current of ESD Generator Tr is 0.7 to 1ns, due to the short increasing time, the disturbance frequency can extend to 500MHz
(D)ESD Test Level
|Contact Discharge||Air Discharge|
|Level||Test Voltage/KV||Level||Test Voltage/KV|
(E)ESD Discharge Method
The electrostatic discharge test consists of two parts: direct discharge and indirect discharge
1. Direct discharge:
The direct discharge is to simulate the human body or other equipment with power discharge directly, which contains contact discharge and air discharge:
a. Contact discharge: for bare metallic part of the surface of the device.
Air discharge: for the device surface covered with insulating substance.
2. Indirect discharge:
For horizontal coupling plate and vertical coupling plate discharge, there is a certain distance for the coupling plate from the equipment, and through two pieces of 470k ohm resistors to ground, so when the coupling plate discharge, the electrostatic of coupling board will not immediately release into the ground, but to form an electrostatic field sourced by coupling plate and interfere to equipment.
(F)Test Result Judgement
|Level||After ESD Test||Result|
|A||No effect, the function is normal during test process||Qualified|
|B||The function is affected temporary but will recover.||Qualified|
|C||The function appears abnormal situation and needs to reset or re-start by hand.||Unqualified|
|D||The function won’t recover any more even re-start and damaged.||Unqualified|