TIM-5H
-
Hardware
Integration
Manual
Design-In
GPS.G5-MS5-07015-A-1
u-blox
proprietary
Page 17
your position is our focus
2.7 Layout Design-In Checklist
Follow
this
checklist
for
the
Layout
design
to
get
an
optimal
GPS
performance.
Layout optimizations (
)
Is
the
GPS
module
placed
according
to
the
recommendation
in
Section 2.8.3
?
Has
the
Grounding
concept
been
followed
(see
Section 2.8.4
)?
Has
the
micro
strip
been
kept
as
short
as
possible?
Add
a
ground
plane
underneath
the
GPS
module
to
reduce
interference.
For
improved
shielding,
add
as
many
vias
as
possible
around
the
micro
strip,
around
the
serial
communication
lines,
underneath
the
GPS
module
etc.
Calculation of the micro strip (
The
micro
strip
must
be
50
Ohms
and
be
routed
in
a
section
of
the
PCB
where
minimal
interference
from
noise
sources
can
be
expected.
In
case
of
a
multi-layer
PCB,
use
the
thickness
of
the
dielectric
between
the
signal
and
the
1st
GND
layer
(typically
the
2nd
layer)
for
the
micro
strip
calculation.
If
the
distance
between
the
micro
strip
and
the
adjacent
GND
area
(on
the
same
layer)
does
not
exceed
5
times
the
track
width
of
the
micro
strip,
use
the
“Coplanar
Waveguide”
model
in
AppCad
to
calculate
the
micro
strip
and
not
the
“micro
strip”
model.
2.8 Layout
This
section
provides
important
information
for
designing
a
reliable
and
sensitive
GPS/GALILEO
system.
GPS
signals
at
the
surface
of
the
Earth
are
about
15dB
below
the
thermal
noise
floor.
Signal
loss
at
the
antenna
and
the
RF
connection
must
be
minimized
as
much
as
possible.
When
defining
a
GPS
receiver
layout,
the
placement
of
the
antenna
with
respect
to
the
receiver,
as
well
as
grounding,
shielding
and
jamming
from
other
digital
devices
are
crucial
issues
and
need
to
be
considered
very
carefully.
2.8.1 Footprint
25.4
±
0.1
mm
[1000
±
4
mil]
25
.4
±
0.
1
mm
[1
0
0
0
±
4
mil
]
1.9
mm
[75
mil]
2.8
mm
[110
mil]
1.277
mm
[50.27
mil]
1.5
mm
[59
mil]
0.8
mm
[32
mil]
1.0mm
[39
mil]
0.8
mm
[32
mil]
1.0mm
[39
mil]
0.8
mm
[32
mil]
Figure 4: Recommended footprint
