Electronic Component News   Calculating dynamic resistance to
help choose an ESD protective device Thu, 08/05/2010 - 12:29pm
Electronic medical devices, especially those that come into
contact with the human body, are at risk for electrostatic
discharge (ESD.) Inadequate protection may damage the IC or
interfere with communications critical to patient care. This
article shows how to choose an ESD device that will give the
best chance of a successful first pass design.  ESD protection
is vital for medical electronics. However, most datasheets for
ESD protective devices leave out the most important piece of
information: how much protection the device will actually
provide.   Some basic ESD topologies and their typical “turn-on”
characteristics  (Note: The ESD threat/pulse is defined by the
IEC61000-4-2 standard shown in Fig. 1.). We will focus on
silicon devices because they tend to give the best ESD clamping,
but the points apply to just about any ESD device.  The two most
common silicon protection devices ar