Eos/Esd/Emi Precautions - u-blox M8 Series Hardware Integration Manual

000000

4.3 EOS/ESD/EMI precautions

When integrating GNSS positioning modules into wireless systems, careful consideration must be
given to electromagnetic and voltage susceptibility issues. Wireless systems include components
that can produce Electrical Overstress (EOS) and Electro-Magnetic Interference (EMI). CMOS devices
are more sensitive to such influences because their failure mechanism is defined by the applied
voltage, whereas bipolar semiconductors are more susceptible to thermal overstress. The following
design guidelines are provided to help in designing robust yet cost-effective solutions.
⚠
Only Separated or Safety Extra-Low Voltage (SELV) circuits are to be connected to the module
including interfaces and antennas.
⚠
To avoid overstress damage during production or in the field it is essential to observe strict
EOS/ESD/EMI handling and protection measures.
⚠
To prevent overstress damage at the receiver RF_IN, never exceed the maximum input power.
Electrostatic discharge (ESD)
Electrostatic discharge (ESD) is the sudden and momentary electric current that flows
between two objects at different electrical potentials caused by direct contact or
induced by an electrostatic field. The term is usually used in the electronics and other
industries to describe momentary unwanted currents that may cause damage to
electronic equipment.
ESD handling precautions
ESD prevention is based on establishing an Electrostatic Protective Area (EPA). The EPA can be a
small working station or a large manufacturing area. The main principle of an EPA is that there are no
highly charging materials near ESD sensitive electronics, all conductive materials are grounded,
workers are grounded, and charge build-up on ESD sensitive electronics is prevented. International
standards are used to define typical EPA and can be obtained for example from International
Electrotechnical Commission (IEC) or American National Standards Institute (ANSI).
GNSS positioning modules are sensitive to ESD and require special precautions when handling.
Particular care must be exercised when handling patch antennas, due to the risk of electrostatic
charges. In addition to standard ESD safety practices, the following measures should be taken into
account whenever handling the receiver.
 Unless there is a galvanic coupling between the local GND (that is,
the work table) and the PCB GND, then the first point of contact
when handling the PCB must always be between the local GND and
PCB GND.
 Before mounting an antenna patch, connect ground of the device.
 When handling the RF pin, do not come into contact with any
charged capacitors and be careful when contacting materials that
can develop charges (e.g. patch antenna ~10 pF, coax cable ~50 -
80 pF/m, soldering iron).
 To prevent electrostatic discharge through the RF input, do not
touch any exposed antenna area. If there is any risk that such
exposed antenna area is touched in non-ESD protected work area,
implement proper ESD protection measures in the design.
UBX-16010549 - R08
C1-Public
NEO-M8L - Hardware integration manual
Product handling Page 19 of 28