User's Manual

page 27/64

Note d’étude / Technical document : URD1– OTL

5665.3

– 003 / 72238 Edition 01

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Figure 27: RF_TX burst indicator

4.13 BACKUP BATTERY

4.13.1 Backup battery function feature

4.13.1.1 With backup battery

A backup battery can be connected to the module in order to supply internal RTC (Real Time Clock) when the

main power supply is removed. Thus, when the main power supply is removed, the RTC is still supplied and the

module keeps the time register running.

With external backup battery:

• If VBAT < 3V, internal RTC is supplied by VBACKUP.

• If VBAT ≥3V, internal RTC is supplied by VBAT.

4.13.1.2 Without backup battery

Without backup battery

• If VBAT ≥ 1.5V, internal RTC is supplied by VBAT.

• If VBAT < 1.5V, internal RTC is not supplied.

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VBACKUP input of the module has to be connected to a 10µF capacitor (between VBACKUP and GND).

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SAGEMCOM does not recommend to connecting VBACKUP signal to VBAT as for former SAGEMCOM

MOXX modules.

4.13.2 Current consumption on the backup battery

When the power supply is removed, the internal RTC will be supplied by backup battery.

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To calculate the backup battery capacity, consider that current consumption for RTC on the backup

battery is up to 1000µA depending on the temperature.

RF_TX

HiLoNC

VBAT