Design-In; Power Management; Connecting Power - u-blox NEO-5 Series Hardware Integration Manual

2 Design-In

For migrating existing ANTARIS
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 Figure 2). Power to RTC and BBR is supplied from
VCC in this case.
VCC
J1
V_BCKP
Figure 2: Backup Battery and Voltage
NEO-5 - Hardware Integration Manual
GPS.G5-MS5-08003-A2
®
4 product designs to u-blox 5 please refer to Appendix A.
Module Voltage Supply
Voltage
Supervisor
RTC and Battery Backup RAM (BBR)
Preliminary
u-blox proprietary
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Design-In
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