ZOE-M8 series - Hardware integration manual
UBX-16030136 - R09
Design-in
Page 22 of 34
Production information
2.14.4
EOS protection measures
EOS protection measures as shown in Figure 15 are recommended for any designs combining wireless
communication transceivers (for example, GSM, GPRS) and GNSS in the same design or in close
proximity.
Passive antennas
Active antennas (without internal filter which need
the SiP antenna supervisor circuits)
C
D
LNA with appropriate ESD rating
and maximum input power.
Figure 15: 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, any electronic device near the GNSS receiver can emit noise that can lead to EMI
disturbances or damage (see section 2.3.4).
The following elements are critical regarding EMI:
Unshielded connectors (for example, pin rows)
Weakly shielded lines on PCB (for example, on top or bottom layer and especially at the border of
a PCB)
Weak GND concept (for example, 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
http://www.murata.com/products/emc/knowhow/pdf/4to5e.pdf
Improved EMI protection can be achieved by inserting a resistor or, better yet, a ferrite bead or an
inductor (see Table 16) into any unshielded PCB lines that are connected to the GNSS receiver. Place
the resistor as close as possible to the GNSS receiver pin.
Alternatively, feed-through capacitors with good GND connection can be used to protect, for example,
the VCC supply pin against EMI. A selection of feed-through capacitors are listed in Table 16.
