Product Info

Smart LTE Module Series
SC20 Hardware Design
SC20_Hardware_Design 40 / 130
3.5.2. Turn off Module
Set the PWRKEY pin low for at least 1s, and then choose to turn off the module when the prompt window
comes up.
The other way to turn off the module is to drive PWRKEY to a low level for at least 8s. The module will
execute forced shutdown. The forced power-down scenario is illustrated in the following figure.
VBAT
PWRKEY
Others
>8s
Power down
Figure 9: Timing of Turning off Module
3.6. VRTC Interface
The RTC (Real Time Clock) can be powered by an external power source through VRTC when the
module is powered down and there is no power supply for the VBAT. The external power source can be
capacitor or rechargeable battery (such as coil cells) according to application demands. The following are
some reference circuit designs when an external battery or capacitor is utilized for powering RTC.
Coin Cell
Module
RTC
Core
VRTC
Figure 10: RTC Powered by Coin Cell