Design Guide

ElectroStatic Discharge (ESD) Considerations
A DIVISION OF TRIMBLE
118 Appendix C: Environmental Considerations
ElectroStatic Discharge (ESD) Considerations
WARNING!
The ThingMagic Nano antenna port may be susceptible to damage from
Electrostatic Discharge (ESD). Equipment failure can result if the antenna or
communication ports are subjected to ESD. Standard ESD precautions should
be taken during installation to avoid static discharge when handling or making
connections to the ThingMagic Nano reader antenna or communication ports.
Environmental analysis should also be performed to ensure static is not building
up on and around the antennas, possibly causing discharges during operation.
ESD Damage Overview
In ThingMagic Nano-based reader installations where readers have failed without a
known destructive event, ESD has been found to be the most common cause. Failures
due to ESD tend to be in the ThingMagic Nano power amplifier section (PA). PA failures
typically manifest themselves at the software interface in the following ways:
RF operations (read, write, etc.) respond with Assert - 7F01 - indicating a a fatal
error. This is typically due to the module not being able to reach the target power
level due to PA damage.
RF operations (read, write, etc.) respond with No Antenna Connected/Detected
even when a known good antenna is attached.
Unexpected Invalid Command errors, indicating command not supported, when that
command had worked just fine shortly before. The reason a command becomes
suddenly not supported is that the reader, in the course of its self protection routines,
has returned to the bootloader to prevent any further damage. This jump to boot
loader caused by power amp damage occurs at the start of any read tag commands.
Ultimately determining that ESD is the root cause of failures is difficult because
confirmation is only possible if the failed components are isolated, taken apart, and
examined under high power microscopy. Often, concluding that ESD was the cause of a
failure is inferred if conditions that could produce ESD are present, anti-ESD precautions
have not been taken, and other possible causes are eliminated.
ESD discharges come with a range of values, and like many things in life there is the
“matter of degree”. For many installations, the ThingMagic Nano has been successfully
deployed and operates happily. For these, there is no failure issue, ESD or otherwise. For
a different installation that with bare ThingMagic Nano, has a failure problem from ESD,
there will be some distribution of ESD intensities occurring. Without knowledge of a limit in