Specifications

LEON-G100/G200 - System Integration Manual
GSM.G1-HW-09002-C Preliminary System description
Page 26 of 75
the V_BCKP voltage within its valid range for around 10 hours at 25°C, after the VCC supply is removed. These
capacitors will let the time reference run during a disconnection of the battery.
Figure 12: Real time clock supply (V_BCKP) application circuits using a 100 µF capacitor to let the RTC run for ~50 seconds at
25°C or using a 70 mF capacitor to let the RTC run for ~10 hours at 25°C when the VCC supply is removed
1.6 System functions
1.6.1 Module power on
The power-on sequence of the module is initiated in one of 4 ways:
Rising edge on the VCC pin to a valid voltage as module supply
Falling edge on the PWR_ON signal
RTC alarm
Rising edge on the V_CHARGE and CHARGE_SENSE to a valid voltage for charger detection (LEON-G200
only)
1.6.1.1 Rising edge on VCC
When a battery supply is connected to the VCC pin, the battery supervision circuit controls the subsequent
activation of the power up state machines: the module is switched-on if the battery is connected for the first
time and the voltage rises up to the valid limit of operation (See LEON-G100/G200 Data Sheet [1]).
1.6.1.2 Falling edge on the PWR_ON
Power-on sequence of the module starts when a falling edge occurs on the PWR_ON signal.
The electrical characteristics of the PWR_ON input pin are different from the other digital I/O interfaces: the high
and the low logic levels have different operating ranges and the pin is tolerant against voltages up to the battery
voltage. The detailed electrical characteristics are described in the datasheet.
PWR_ON pin has high input impedance and is weakly pulled to the high level on the module. Avoid to
keep it floating in noisy environment: to hold the high logic level stable, it is suggested to add a pull-up to
the V_BCKP supply.
Force the PWR_ON input pin to the low level for at least 50 ms to cause a switch-on of the module, also if the
power-on sequence is triggered by a falling edge on the PWR_ON signal.
If PWR_ON input is connected to an external device (e.g. application processor), use an open drain output of the
external device with an external pull-up. Connect the pull-up to V_BCKP supply or to another supply rail present
LEON-G100/G200
2
V_BCKP
100 µF
GRM43SR60J107M
+
LEON-G100/G200
2
V_BCKP
70 mF
XH414H-IV01E
+
4.7 k
LEON-G100/G200
2
V_BCKP
100 µF
GRM43SR60J107M
+
LEON-G100/G200
2
V_BCKP
70 mF
XH414H-IV01E
+
4.7 k