IEC 61000-4-2:2008 

Electromagnetic compatibility (EMC) - Part 4-2: Testing and measurement techniques - Electrostatic discharge immunity test

Electrostatic Discharge (ESD) tests are used to verify complete systems and duplicate disturbances in installations. These tests contribute to identifying immunity failures caused by bad cabling or system composition, as well as grounding problems.

IEC 61000-4-2 is an international test standard that outlines electromagnetic immunity requirements for electronic equipment when exposed to electrostatic discharge (ESD) generated from a human body or metal objects. The standard assumes that the source is an electrified human body discharge and testing simulates the current waveform generated in those conditions.

EUT Test Setup

The direct discharge test simulates the human body model of electrostatic discharge and must be set up to recreate similar conditions. It is important to make sure that you have the proper grounding system in place before you begin testing. When using a tabletop for testing, you want to have a horizontal coupling plane on top of the table but below an insulation sheet. This should be connected to a ground reference plane on the floor using a 2 x 470k? bleed resistor cable


If the EUT is too large for a tabletop, place the EUT on an insulation pallet that is at least 0.1m in height. For the indirect contact discharge part of the test, a vertical coupling plane should be set up 10cm from the EUT, and also connected to the ground reference plane using the bleed resistors. Once set up, a power supply should be connected to the EUT and ESD gun. It is important to make sure that the room where the test is conducted is at a temperature of 15°C to 35°C and relative humidity is between 30% and 60%.

The test procedure is rather simple. For direct discharge, place the ESD gun to the point of test on the EUT, and discharge at 1-second intervals. This should be performed at least 10 times at both positive and negative polarities, and results recorded. For an indirect discharge test, the same process is repeated except that the discharge goes to the vertical or horizontal coupling plane, rather than directly to the EUT. Multiple discharge points may be required for testing, depending on the EUT.

The results are classified in 4 ways:
 

• Normal operation within the tolerance of specification
• Temporary degradation or loss in operation or function, which is able to be recovered by self-recovery function
• Temporary degradation or loss in operation or function, which needs to be recovered by user intervention or system reset.
• Damage of the system or software, and unrecoverable degradation and loss of function or data.