NEO-5
-
Hardware
Integration
Manual
Preliminary
Design-In
GPS.G5-MS5-08003-A2
u-blox
proprietary
Page 15
your position is our focus
•
Decide
whether
TIMEPULSE
options
are
required
in
your
application
and
connect
the
appropriate
pins
on
your
module
•
Connect
pins
8
and
9
together.
•
NEO-5
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
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
VCC_RF
GND
GND
Figure 5: Recommended wiring for active antennas
•
For
optimal
performance,
it
is
important
to
place
the
inductor
as
close
to
the
microstrip
as
possible.
illustrates
the
recommended
layout
and
how
it
should
not
be
done.
GND
Microstrip
GND
RF
_IN
Antenna Supply Voltage
(e.g. VCC_RF)
Inductor L
GND
GND
Antenna Supply Voltage
(e.g. VCC_RF)
Inductor L
Microstrip
RF
_IN
Good
Bad
Figure 6: Recommended layout for connecting the antenna bias voltage for NEO-5