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SARA-R4 series - System integration manual
UBX-16029218 - R20
Design-in
Page 77 of 128
C1-Public
2.4.5.2
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
and
•
The
ANT
pin must be 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
ANT
pin (C2) must be placed in series to the 50
RF line.
•
The
ANT_DET
pin must be connected to the 50
transmission line by means of a sense line.
•
Choke inductor in series at the
ANT_DET
pin (L1) must be 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) are provided as
ANT_DET
ESD protection.
•
The additional high pass filter (C3 and L2) is provided as ESD immunity improvement.
SARA module
C2
R1
D1
C1
L1
J1
C3 L2
Figure 47: Suggested layout for antenna detection circuit on application board