Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
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Figure 3-27
RF layout reference
The RF traces are wide 0.5 mm;
leave space at least 0.5 mm
between the coppers. Drill
enough grounding holes.
Ensure that the ground pins on both sides of the
antenna are grounded completely and they form
a complete circle with grounding copper.
ESD protection is built in module. For special ESD protection, an ESD diode can be placed close to the
antenna. But ensure using a low junction capacitance ESD diode. The junction capacitance should be less
than 0.5 pF, otherwise the RF signal will be attenuated. RCLAMP0521P from Semtech, or ESD5V3U1U
from Infineon, can be used here.
On the PCB, keep the RF signals and RF components away from high-speed circuits, power supplies,
transformers, great inductors, the clock circuit of single-chip host, etc.
3.8.2 Recommended RF Connection
If you adopts RF cables for connections, the GSC RF connector MM9329-2700RA1 from Murata is
recommended. Figure 3-28 shows the encapsulation specifications.
Figure 3-28
Encapsulation specifications of Murata RF connector
RF cable can also be connected to the module by soldering. In this manner, you must ensure proper
soldering in case of damage that lowers RF performance. Figure 3-29 shows the pictures of these two
connections.
Figure 3-29
RF connections
