User's Manual

ElectroStatic Discharge (ESD) Considerations
A DIVISION OF TRIMBLE
Appendix C: Environmental Considerations 119
charge leakage, and provides a high pass characteristic that attenuates discharge
events. (This also makes the antenna compatible with the ThingMagic Nano antenna
detect methods.)
Install a Minicircuits SHP600+ high pass filter in the cable run at the ThingMagic Nano
(or Vega or other finished reader) end. This additional component will reduce
transmit power by 0.4 dB which may affect read range in some critical applications.
However the filter will significantly attenuate discharges and improve the ThingMagic
Nano ESD survival level.
Note
The SHP600+ is not rated for the full +31.5 dBm output of the ThingMagic
Nano reader at +85 degree C. Operation at reduced temperature has been
anecdotally observed to be OK, but has not been fully qualified by
ThingMagic.

90 V Lightning Arrestors, such as the Terrawave Solutions Model TW-LP-RPTNC-P-
BHJ have been shown to be effective in suppressing ESD. This model contains a gas
discharge tube which must be replaced periodically.
Install a Diode Clamp* circuit immediately outboard from the SHP600 filter. This will
reduce transmit power by an additional 0.4 dB, but in combination with the SHP600
will further improve the ThingMagic Nano ESD survival level. (Needs DC power,
contact [e-mail] for availability.)
Further ESD Protection for Reduced RF Power Applications
In addition to the protective measures recommended above, for applications where
reduced ThingMagic Nano RF power is acceptable and ESD is suspected the following
protective measures can also be applied:
Install a one watt attenuator with a decibel value of +30 dBm minus the dBm value
needed for tag power up. Then run the reader at +30 dBm instead of reduced
transmit power. This will attenuate inbound ESD pulses by the installed decibel
value, while keeping the tag operation generally unchanged. Attenuators of 6 dB
have been shown to not adversely effect read sensitivity. Position the attenuator as
close to the ThingMagic Nano as feasible.
As described above add the SHP600 filter immediately adjacent to the attenuator, on
the antenna side.
Add Diode Clamp, if required, adjacent to the SHP600, on the antenna side.