Specifications

LEON-G100/G200 - System Integration Manual
GSM.G1-HW-09002-C Preliminary System description
Page 28 of 75
The power-on sequence is described in Figure 14.
VCC
V_BCKP
PWR_ON
LDOs
RESET_N
System State ON
BB Pads State Operational
don't care
Tristate
Reset
OFF
don't care
Start-up
event
Valid
VCC
Figure 14: Power on sequence description
1.6.2 Module power off
LEON-G100/G200 can be switched-off by one of the following switch-off events:
Via AT command AT+CPWROFF (more details in u-blox AT Commands Manual [2]). This is the only way
to switch off the module.
An under-voltage shutdown will be done if VCC falls below the valid operating limit.
After a switch-off event has been triggered, the digital pins are locked in tri-state by the module. All internal
voltage regulators except the RTC supply are turned off in a defined power-off sequence.
To avoid an increase of module current consumption in power-down mode, any external signal connected
to the module digital pins (UART interface, Digital audio interface, HS_DET, GPIOs) must be set low or tri-
stated when the module is in the not-powered or power-off modes. If the external signals connected to the
module digital pins cannot be set low or tri-stated, insert a switch (e.g. Texas Instruments
SN74CB3Q16244, or Texas Instruments TS5A3159, or Texas Instruments TS5A63157) between the two-
circuit connections. Set the switch to high impedance when the module is in power-down mode (to avoid
an increase of the module power consumption).
The power-off sequence is described in Figure 15.