ZOE-M8B - System Integration Manual
UBX-17045131 - R04
Contents
Page 27 of 42
Production Information
Passive antennas
Active Antennas
A
B
LNA with appropriate ESD
rating
RF ESD protection diode
Figure 19: ESD Precautions
2.14.3
Electrical Overstress (EOS)
Electrical Overstress (EOS) usually describes situations when the maximum input power exceeds the
maximum specified ratings. EOS failure can happen if RF emitters are close to a GNSS receiver or its
antenna. EOS causes damage to the chip structures.
If the
RF_IN
is damaged by EOS, it’s hard to determine whether the chip structures have been
damaged by ESD or EOS.
2.14.4
EOS protection measures
EOS protection measures as shown in Figure 20 are recommended for any designs combining wireless
communication transceivers (e.g. GSM, GPRS) and GNSS in the same design or in close proximity.
Passive antennas
Active Antennas
C
D
LNA with appropriate ESD
rating and maximum input
power.
Figure 20: EOS and ESD Precautions
2.14.5
Electromagnetic interference (EMI)
Electromagnetic interference (EMI) is the addition or coupling of energy, which causes a spontaneous
reset of the GNSS receiver or results in unstable performance. In addition to EMI degradation due to
self-jamming (see Section 2.3.3) , any electronic device near the GNSS receiver can emit noise that
can lead to EMI disturbances or damage.
The following elements are critical regarding EMI:
•
Unshielded connectors (e.g. pin rows etc.)
•
Weakly shielded lines on PCB (e.g. on top or bottom layer and especially at the border of a PCB)
•
Weak GND concept (e.g. small and/or long ground line connections)
EMI protection measures are recommended when RF emitting devices are near the GNSS receiver. To
minimize the effect of EMI a robust grounding concept is essential. To achieve electromagnetic
robustness follow the standard EMI suppression techniques.
http://www.murata.com/products/emc/knowhow/index.html
