SARA-N2 / N3 series - System integration manual
UBX-17005143 - R13
Design-in
Page 54 of 95
C1-Public
2.4.3.2
Guidelines for ANT_DET layout design
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
SARA module
C2
R1
D1
C1
L1
J1
C3 L2
Figure 29: Suggested layout for antenna detection circuit on application board
The antenna detection circuit layout suggested in
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
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.