ANSI C63.16 elucidates explanations, best practices, and guidance for avoiding the pitfalls associated with electrostatic discharge (ESD) testing to IEC and other international standards. ESD standards are provided and should be considered a supplement to these standards, rather than a replacement. Unique ESD test procedures related to connecting charged peripherals to equipment in use are also included.
ANSI C63.16 Foreword
This standard for performing electrostatic discharge (ESD) testing incorporates the latest research in ESD waveform characterization and strives to ensure product quality through proper operation in actual equipment installations. The discharge source is based on the hand/metal model: discharges from a human with an intervening metal object between the hand and point of contact. The modes of contact discharge and air discharge are specified, as well as direct (on the product) and indirect (near the product) discharge points.
One of the primary goals of this standard will be to address the deficiencies in existing ESD standards, including IEC 61000-4-2. Existing ESD standards were written based on the state of the art in measurement technology and the industry’s understanding of the ESD phenomena at the time, and they have done much to improve the immunity of electronic devices to ESD.
The variation of human-metal ESD is large over typical voltage arc length ranges and differs from furniture ESD or human-skin ESD. The problem of finding a waveform that provides a reasonable level of product protection is difficult and leads to a compromise. For example, a present requirement of IEC 61000-4-2 is a 0.7 to 1 ns rise time, which is slower than many actual ESD events. Faster rise times like 200 ps will cover more of the very often occurring low voltage ESDs and the fast-rising high voltage ESDs (usually in very dry air), but it may be too fast compared to many ESDs above 4 kV in the moderately humid air. With contact ESD testing, the rise time is fixed for all voltage ranges. If 200 ps rise time is chosen then this would create over design with high voltages or non-dry air conditions.
ANSI C63.16 Test Environments
Controlled Environment: An environment that has relative humidity controlled to be always greater than 20% and specified minimum conductivity of floors, work surfaces, and furnishings (chairs, carts, etc). This environment does not necessarily apply to all product types.
Standard Environment: Typical office or home environment, where relative humidity and material/surface conductivity are not controlled but relative humidity is usually greater than 10%.
Extreme Environment: an environment with characteristics of either
Stress Levels From ANSI C63.16
- Extremely low relative humidity (typically less than 10%)
- Routine activities that generate high static electricity levels
- Equipment/functions with life-threatening or disastrous consequences, such as life support systems, essential human safety systems, or financial systems.
ANSI C63.16 has test level criteria for different types of equipment; Information Technology (IT), Consumer Electronic Equipment and Telecommunications equipment.
All tests are to completed with 50 discharges at positive and negative polarities.
Pass/Fail Criteria For ANSI C63.16
|DISCHARGE VOLTAGE, CONTROLLED ENVIRONMENT
|| DISCHARGE VOLTAGE, STANDARD ENVIRONMENT
- If more than 1 error occurs in the first 50 discharges applied to a test point, the EUT fails the test at that test point and test level.
- If 1 error occurs in the first 50 discharges applied to a test point, a second test is run at that test point applying 100 new discharges. If no error occurs in this set of 100 discharges, the EUT passes the test at that test point. If more than one error occurs in this set of 100 discharges, the EUT fails the test. If exactly 1 error occurs in this set of 100 discharges, a third test is performed.
- The third test is to the repetition of the point. If no error occurs in this set of 100 discharges, the EUT passes the test at that test point. If 1 or more errors occur in this set of 100 discharges, the EUT fails the test.