TIM-5H
-
Hardware
Integration
Manual
Design-In
GPS.G5-MS5-07015-A-1
u-blox
proprietary
Page 10
your position is our focus
2 Design-In
For
migrating
existing
ANTARIS
®
4
product
designs
to
u-blox
5
please
refer
to
Appendix A
In
order
to
obtain
good
performance
with
a
GPS
receiver
module,
there
are
a
number
of
points
that
require
careful
attention
during
the
design-in.
These
include:
•
Power
Supply
Good
performance
requires
a
clean
and
stable
power
supply.
•
Interfaces
Ensure
correct
wiring,
rate
and
message
setup
on
the
module
and
your
host
system.
•
Antenna
interface
For
optimal
performance
seek
short
routing,
matched
impedance
and
no
stubs.
2.1 Power Management
2.1.1 Connecting Power
u-blox
5
receivers
have
three
power
supply
pins:
VCC
,
V_BCKP
and
VDDUSB
.
2.1.1.1
VCC - Main Power
The
main
power
supply
is
fed
through
the
VCC
pin.
During
operation,
the
current
drawn
by
the
u-blox
5
GPS
module
can
vary
by
some
orders
of
magnitude,
especially,
if
low-power
operation
modes
are
enabled.
It
is
important
that
the
system
power
supply
circuitry
is
able
to
support
the
peak
power
(see
datasheet
for
specification)
for
a
short
time.
In
order
to
define
a
battery
capacity
for
specific
applications
the
sustained
power
figure
shall
be
used.
2.1.1.2
V_BCKP - Backup Battery
In
case
of
a
power
failure
on
pin
VCC
,
the
real-time
clock
and
backup
RAM
are
supplied
through
pin
V_BCKP
.
This
enables
the
u-blox
5
receiver
to
recover
from
a
power
failure
with
either
a
Hotstart
or
a
Warmstart
(depending
on
the
duration
of
VCC
outage)
and
to
maintain
the
configuration
settings.
If
no
backup
battery
is
connected,
the
receiver
performs
a
Coldstart
at
power
up.
If
no
backup
battery
available
connect
the
V_BCKP
pin
to
GND (or VCC)
.
As
long
as
VCC
is
supplied
to
the
u-blox
5
receiver,
the
backup
battery
is
disconnected
from
the
RTC
and
the
backup
RAM
in
order
to
avoid
unnecessary
battery
drain
(see
Power
to
RTC
and
BBR
is
supplied
from
VCC
in
this
case.
VCC
V_BCKP
Voltage
Supervisor
Module Voltage Supply
RTC and Battery Backup RAM (BBR)
J1
Figure 2: Backup Battery and Voltage
