Design Guide

ElectroStatic Discharge (ESD) Considerations
A DIVISION OF TRIMBLE
Appendix C: Environmental Considerations 121
Note
The SHP600+ is rated for the full +27dBm (0.5 W) output of the ThingMagic
Nano reader. Care must be taken if it is operated at higher RF input levels at
high temperatures.
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 half watt attenuator with a decibel value of +27 dBm minus the dBm value
needed for tag power up. Then run the reader at +27 dBm instead of reduced
transmit power. This will attenuate inbound ESD pulses by the installed decibel
value, while keeping the tag operation generally unchanged. Note that the receive
sensitivity will be reduced by this same amount. 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.