AMY-5M
-
Hardware
Integration
Manual
Objective
Specification
Design-In
GPS.G5-MS5-08207
u-blox
proprietary
Page 17
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2.1.10 Active Antenna Supply
With
AMY-5M
modules
active
antennas
are
supplied
via
an
external
coil
or
circuit.
AMY-5M
modules
do
not
provide
the
antenna
bias
voltage
for
active
antennas
on
the
RF_IN
pin.
It
is
therefore
necessary
to
provide
this
voltage
outside
the
module
via
an
inductor
as
indicated
in
Figure
7.
u-blox
recommends
using
an
inductor
from
Coilcraft
(0402CS-36NX).
Alternative
parts
can
be
used
if
the
inductor’s
resonant
frequency
matches
the
GPS
frequency
of
1575.4MHz.
Low Noise Amplifier
Active Antenna
RF_IN
VDD_3V
36n
or 27n
100n
C
1
L
1
C
2
10
Ω
Figure 7: Recommended wiring for active antennas
For
C
and
L
values
see
Component
Selection
Section
B.
•
For
optimal
performance,
it
is
important
to
place
the
inductor
as
close
to
the
microstrip
as
possible.
Figure
8
illustrates
the
recommended
layout
and
how
it
should
not
be
done.
Microstrip
RF
_IN
Antenna Supply Voltage
(e.g. VDD_3V)
Inductor L
Antenna Supply Voltage
(e.g. VDD_3V)
Inductor L
Microstrip
Good
Bad
RF
_IN
Figure 8: Recommended layout for connecting the antenna bias voltage for AMY-5M
