User's Manual

• Elements for ESD protection should be placed on all pins that are accessible from the

outside and should be placed close to the accessible area. For example, the RF-pin is

accessible when using an external antenna and should be protected.

• ESD protection for the antenna connection must be chosen such as to have a minimum

effect on the RF signal. For example, a protection diode with low capacitance such as

the LXES15AAA1-100 or a 68 nH air-core coil connecting the RF-line to ground give

good results.

• Placeholders for optional antenna matching or additional ﬁltering are recommended.

• The antenna path should be kept as short as possible.

Again, no ﬁxed values can be recommended, as they depend on the inﬂuenc-

ing circumstances of the application (antenna, interferences etc.).

Figure 8: Layout

• To avoid the risk of short circuits and interference there should be no routing under-

neath the module on the top layer of the baseboard.

• On the second layer, a ground plane is recommended, to provide good grounding and

shielding to any following layers and application environment.

• In case of integrated antennas it is required to have areas free from ground. This area

should be copied from the evaluation board.

• The area with the integrated antenna must overlap with the carrier board and should

not protrude, as it is matched to sitting directly on top of a PCB.

• Modules with integrated antennas should be placed with the antenna at the edge of

the main board. It should not be placed in the middle of the main board or far away

from the edge. This is to avoid tracks beside the antenna.