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NEO-M8L - Hardware integration manual
UBX-16010549 - R08
Product handling
Page 21 of 28
C1-Public
Small passive antennas (<2 dBic
and performance critical)
Passive antennas (>2 dBic or
performance sufficient)
Active antennas (without internal filter which
need the module antenna supervisor circuits)
D
RF
_
IN
G
N
S
S
R
e
c
e
iv
e
r
LNA
GPS
Bandpass
Filtler
E
RF
_
IN
G
N
S
S
R
e
c
e
iv
e
r
L
GPS
Bandpass
Filtler
F
LNA with appropriate ESD rating
and maximum input power
GNSS Band pass Filter: SAW or
Ceramic with low insertion loss
and appropriate ESD rating
Figure 14: EOS and ESD precautions
Electromagnetic interference (EMI)
Electromagnetic interference (EMI) is the addition or coupling of energy causing a spontaneous reset
of the GNSS receiver or resulting in unstable performance. In addition to EMI degradation due to self-
jamming (see section 1.5) 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)
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
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 4) into any unshielded PCB lines 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 is listed in Table 4.
4.4
Safety precautions
The automotive grade NEO-M8L-01A modules must be supplied by an external limited power source
in compliance with the clause 2.5 of the standard IEC 60950-1. In addition to external limited power
source, only Separated or Safety Extra-Low Voltage (SELV) circuits are to be connected to the module
including interfaces and antennas.
☞
For more information about SELV circuits see section 2.2 in Safety standard IEC 60950-1 [11].
