Quectel EG91 Series Hardware Design page 42

3.7.2.1. Turn off Module Using the PWRKEY Pin
Driving the PWRKEY pin to a low level voltage for at least 650 ms, the module will execute power-off
procedure after the PWRKEY is released. The power-down scenario is illustrated in the following figure.
3.7.2.2. Turn off Module Using AT Command
It is also a safe way to use AT+QPOWD to turn off the module, which is similar to turning off the module
via PWRKEY pin.
See document [3] for details about the AT+QPOWD.
NOTE
1. To avoid damaging internal flash, do not switch off the power supply when the module works
normally. Only after the module is shut down by PWRKEY or AT command, the power supply can be
cut off.
2. When turning off module with the AT command, keep PWRKEY at high level after the execution of
the command. Otherwise, the module will be turned on again after being shut down.
EG91_Series_Hardware_Design
Figure 13: Power-down Timing
LTE Standard Module Series
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