ESD (Electrostatic Discharge) Testing Standards

Common ESD (Electrostatic Discharge) testing standards include the following :

ANSI/ESD S20.20 : This is a comprehensive electrostatic control standard applicable to the electronics industry. It provides requirements and guidance regarding equipment, grounding, personnel training, processes, and protective measures. 

IEC 61340-5series standards : A series of standards published by the International Electrotechnical Commission (IEC) covering requirements for electrostatic control and resistive materials. The most commonly used standard is IEC 61340-5-1, which covers ESD control procedures, design, and testing methods.

MIL-STD-883 and MIL-STD-750 : These standards are applicable to the US military field and test and verify the reliability and anti-static control of integrated circuits.

JEDEC JS-001 and JEDEC JESD22: These standards, published by the Semiconductor Industry Association (JEDEC), cover ESD testing methods and requirements for electronic components.

These standards provide guidance for ESD testing and protection in various industries. Depending on specific needs, relevant organizations and industries may adopt different standards to ensure the electrostatic control and safety performance of products and equipment.

ESD Electrostatic Discharge Testing Methods

(1) Discharge Modes: Air Discharge and Contact Discharge.

a. Ten discharges per point;

b. Immediately after each discharge, the charge is conducted away with a grounding wire;

c. Test Voltages: ±5KV, ±8KV, and ±15KV.

(2) Test Voltages:

A. Air Discharge requires testing at ±5KV, ±8KV, and ±15KV.

B. Contact Discharge requires testing at ±3KV, ±4KV, and ±8KV.

Site-Based Electrostatic Discharge Testing

Site-based testing is conducted under the conditions of equipment installation. It is typically performed after equipment experiences a setback in the field, as a preliminary assessment, and is agreed upon by the manufacturer and user.

For site-based testing, to facilitate the connection of the grounding return cable of the electrostatic discharge gun, a reference grounding plate should be laid on the ground, maintaining a distance of 0.1m from the test specimen and its system. The material and thickness of the reference grounding plate should be the same as those required for laboratory setup. Where conditions permit, the grounding plate size should be 0.3m × 2m. The reference grounding plate should be connected to the field safety ground or to the grounding terminal of the test specimen and its system. The generator's grounding return cable should be connected to the reference grounding plane closest to the discharge point of the test specimen and its system.

When the test specimen and its system are mounted on a metal table, and the metal table is not safely connected to the field ground, the metal table should be connected to a reference ground plane through a 470kΩ resistance wire at both ends to prevent static electricity buildup. 

Electrostatic Discharge Levels

The standard classifies test levels into four levels: 2kV, 4kV, 6kV, and 8kV for contact discharge; and 2kV, 4kV, 8kV, and 15kV for air gap discharge.

The selection of the test level is related to environmental factors (the drier the environment, the higher the test voltage level). However, for a specific product, the level is often specified in the corresponding product family standard or product standard (along with the conformity assessment criteria for the test specimen).

Electrostatic Discharge Standard Commentary

* The standard uses contact discharge as the preferred discharge method because contact discharge has fewer uncertainties.
* Contact discharge has an extremely steep rise time, resulting in a discharge current waveform containing a wealth of harmonic components. Even with a relatively low test voltage, more stringent test results can be obtained compared to air gap discharge at higher voltages of the same level.