Turn Off Module; Vrtc Interface - Quectel Smart LTE Module Series Hardware Design

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The turn-on timing might be different from the above figure when the module powers on for the first

time.

Make sure that VBAT is stable before pulling down PWRKEY pin. The recommended time between

them is no less than 30ms. PWRKEY cannot be pulled down all the time.

3.5.2. Turn off Module

Pull down PWRKEY for at least 1s, and then choose to turn off the module when the prompt window

comes up.

Another 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

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

rechargeable battery (such as coil cells) according to application demands. The following reference circuit

design when an external battery is utilized for powering RTC.

SC650T_Hardware_Design

Figure 8: Timing of Turning off Module

Coin Cell

Figure 9: RTC Powered by Coin Cell

> 8s

Power down

VRTC

Module

Smart LTE Module Series

SC650T Hardware Design

RTC

Core

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