User's Manual

Table Of Contents
SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08 Objective Specification Design-in
Page 107 of 188
2.4.2.1 Guidelines for ANT_DET layout design
Figure 53 describes the recommended layout for the antenna detection circuit to be provided on the application
board to achieve antenna detection functionality, implementing the recommended schematic described in the
previous Figure 52 and Table 26.
SARA-G340 / SARA-G350
SARA-U2 series module
C2
R1
D1
C1
L1
J1
C3 L2
Figure 53: Suggested layout for antenna detection circuit on application board
The antenna detection circuit layout suggested in Figure 53 is here explained:
The ANT pin is connected to the antenna connector by means of a 50 transmission line, implementing the
design guidelines described in section 2.4.1 and the recommendations of the SMA connector manufacturer
DC blocking capacitor at the ANT pin (C2) is placed in series to the 50 transmission line
The ANT_DET pin is connected to the 50 transmission line by means of a sense line
Choke inductor in series at the ANT_DET pin (L1) is placed so that one pad is on the 50 transmission line
and the other pad represents the start of the sense line to the ANT_DET pin
The additional components (R1, C1 and D1) on the ANT_DET line are placed as ESD protection
The additional high pass filter (C3 and L2) on the ANT line are placed as ESD immunity improvement for
SARA-U2 modules (a series 0 jumper can be mounted for SARA-G340 and SARA-G350 modules instead
of the high pass filter, as no further precaution to ESD immunity test is needed).