User's Manual

UMTS/HSPA Module Series
UG95 Hardware Design
UG95_Hardware_Design Confidential / Released 30 / 67
The power-down scenario is illustrated as the following figure.
VBAT
PWRDWN_N
(Input)
Log off network about 1s to 60s
100ms
RUNNING
Power-down procedure
OFF
Module
Status
STATUS
Figure 12: Timing of Turning off Module
During power-down procedure, module will log off network and save important data. After logging off,
module sends out “OK”, and then sends out POWERED DOWN and shut down the internal power
supply. The power on VBAT pins is not allowed to turn off before the URC “POWERED DOWN” is output
to avoid data loss. If logging off is not done within 60s, module will shut down internal power supply
forcibly.
After that moment, the module enters the power down mode, no other AT commands can be executed
and only the RTC is still active. The power down mode can also be indicated by the STATUS pin.
3.7.2.2. Turn off Module Using AT Command
It is also a safe way to use AT command AT+QPOWD to turn off the module, which is similar to turning off
the module via PWRDWN_N Pin.
Please refer to document [1] for details about the AT command of AT+QPOWD.
3.7.2.3. Automatic Shutdown
The module will constantly monitor the voltage applied on the VBAT, if the voltage 3.5V, the following
URC will be presented:
+QIND: “vbatt”,-1