This Technical Tidbit presents a
short paper by Geoff Weil with measurements on different types of
ESD. Geoff is an excellent designer especially of analog circuits and
especially if they contain high voltage. He designed the well known
KeyTek Mini-Zap™ ESD simulator years ago as well as the KeyTek
ZapMaster™ and several Electrical Fast Transient generators. He is
currently working on voltage-boosted alpha source ionizers and high
voltage pulse generators.
Figure 1 shows the test setup used to generate data for Geoff's Human
Metal Model (HMM) waveforms. He also discusses bare finger tip
discharges (similar to Human Body Model), Charged Device Model, and
Furniture discharges in his paper. Click here
to view the pdf file. Although the test setup is not strictly identical
to that used in standards based ESD testing, it nonetheless give one a
good feel for the characteristics of different type of ESD events.
The data for the finger tip discharge is similar to that in the
Human Body Model, HBM, industry standard test. A description of how
this test relates to other types of ESD testing can be seen in this EDN article
Furniture discharges vary a lot depending on the physical
characteristics of the furniture. In his paper, Geoff describes two
possible types, one of which looks a lot like the discharge from a
charged transmission line, which the long piece of metal resembles.