Design Guide

ElectroStatic Discharge (ESD) Considerations
A DIVISION OF TRIMBLE
Appendix C: Environmental Considerations 119
the statistics of those intensities, there may always be the bigger zap waiting in the wings.
For the bare ThingMagic Nano equipped with the mitigation methods described below,
there will always be the rouge ESD discharge that exceeds any given mitigation, and
results in failure. Fortunately, many installations will have some upper bound on the value
of ESD events given the geometry of that installation.
Several sequential steps are recommended for a) determining the ESD is the likely cause
of a given group of failures, and b) enhancing the ThingMagic Nanoʼs environment to
eliminate ESD failures. The steps vary depending on the required ThingMagic Nano
output power in any given application.
Identifying ESD as the Cause of Damaged Readers
The following are some suggested methods to determine if ESD is a cause of reader
failures, i.e. ESD diagnostics. Please remember- some of these suggestions have the
negative result experiment problem.
Return failed units for analysis. Analysis should be able to say if it is the power
amplifier that has in fact failed, but wonʼt be able to definitively identify that the cause
is ESD. However, ESD is one of the more common causes of PA failure.
Measure ambient static levels with static meter. AlphaLabs SVM2 is such a meter, but
there are others. You may be surprised at the static potentials floating detected.
However, high static doesnʼt necessarily mean discharges, but should be considered
cause for further investigation. High levels that keep changing are highly indicative of
discharges.
Touch some things around the antenna, and operating area. If you feel static
discharges, that qualitatively says quite a bit about what is in front of the antenna.
What actually gets to the ThingMagic Nano is also strongly influenced by the antenna
installation, cabling, and grounding discussed above.
Use the mean operating time statistic before and after one or more of the changes
listed below to quantitatively determine if the change has resulted in an improvement.
Be sure to restart your statistics after the change.
Common Installation Best Practices
The following are common installation best practices which will ensure the readers isnʼt
being unnecessarily exposed to ESD in even low risk environments. These should be
applied to all installations, full power or partial power, ESD or not:
Insure that ThingMagic Nano, reader housing, and antenna ground connection are all
grounded to a common low impedance ground.