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Directive, the EU chose to use international standards
and convert them to European Norms (ENs), rather than
developing a whole new set of “European” standards. Today,
European Norms are essentially identical to standards created
by the IEC or the CISPR - Comité Internationale Spécial des
Perturbations Radioelectrotechnique (International Special
Committee on Radio Interference, IEC).
Why Are IEC 61000-4-2 Compliant Simulators Dominant
Outside Europe?
By making the EMC Directive and others mandatory in the
EU and by passing laws to enforce these directives, any
manufacturer worldwide wanting to do business with any
country that is part of the EU (or any country inside Europe
wanting to expand into other European countries) had to
comply with these IEC and CISPR-based standards. IEC 801-
2 for ESD became IEC 1000-4-2 and then IEC 61000-4-2, and
companies worldwide needed compliant ESD simulators.
With the publication of the first EMC Directive in 1989,
the market for ESD simulators soared. For the first time, an
international standard was in place that forced manufacturers
across the globe to seek ESD simulators with the same output
characteristics, and commercial manufacturers were there to
provide them.5 New simulators are still being designed today
to meet higher voltage requirements, and which add new user
features.
Because of the dominance of the IEC 61000-4-2 and the
wide availability of ESD simulators to meet that standard,
harmonization began to take place naturally. Rather than
having to do multiple different ESD tests, manufacturers
doing business in the EU modified their internal test standards.
As industry standards came due for revision or modifications,
manufacturers pushed them in the direction of harmonization
with the IEC standards. In addition, national standards
organizations were similarly pushed towards harmonization.
Today, harmonized versions of IEC 61000-4-2 for ESD testing
exist in many industry organizations, including ANSI, TIA,
Telcordia, SAE, UL, ISO and others, not to mention national
requirements in counties like China, Korea, Japan, Australia
Figures 5a and 5b: Examples of modern ESD Simulators – a small, and India.
battery operated unit and a 30kV unit for special applications
(photos courtesy of Thermo Fisher Scientific).
Figure 4: A simplified ESD simulator circuit from IEC 61000-4-2
September 2008 Conformity 53
Are IEC 61000-4-2 Based Standards and Simulators the Only
Ones in Use Today?
Certainly not. Although IEC 61000-4-2 and standards
harmonized with it are dominant worldwide for testing
consumer, medical and information technology products, there
are others that are applicable in special circumstances. As an
example, there are ESD standards in the automotive industry,
where there exists not only a general ISO standard, but also
corporate standards from most automotive manufacturers.
Each of these standards still requires a unique set of capacitor
and resistor values for the simulators.
Another example is MIL-STD 883, which requires a
different network and specifies a discharge current waveform
identical to that used for testing individual ICs for ESD in the
production and handling phases.
Two new standards are being developed by the Electrostatic
Discharge Association (ESDA) that have interesting
characteristics, dealing with HMM (human metal model) and
CDE (cable discharge events). Although each has a basis in
the IEC 61000-4-2 standard, they diverge from it in order
to deal with unique applications and characteristics of the
required tests.
HMM - Human Metal Model – Is a New Kind of ESD Simulator
for ESD in the Wings?
Manufacturers who are required to test their products to IEC
610004-2 for ESD have, in turn, been placing that requirement
on the suppliers of sub-assemblies, and more recently on the
suppliers of integrated circuits – specifically those ICs that
will interface directly with the outside world, such as drivers
for USB ports or Ethernet cables. IEC 61000-4-2 is a test
standard describing a simulator and procedures for testing
finished products, procedures that simply cannot be used for
testing ICs. This leaves device manufacturers in a quandary,
since IEC 61000-4-2 was never intended for testing ICs.
So how does one test a single IC pin using a simulator
designed to replicate a human touching devices such as
video displays, computer keyboards, telephones and ATM
machines? Because no standard exists, IC manufacturers are
all using different test methods. Some have an IC laying on
　
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