Turn Off Module; Vrtc Interface - Quectel SC606T Series Hardware Design

Smart Module Series
SC606T Series Hardware Design

3.5.2. Turn Off Module

One way to turn off the module is to pull down PWRKEY for at least 1 s, and then choose to turn off when
the prompt window comes up on the display screen connected to an LCM interface of the module.
Another way is to drive PWRKEY low for at least 8 s, which forces the module to shut down. The forced
power-down timing is illustrated in the following figure.
Figure 9: Power-off Timing

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 supplied to the VBAT. The external power source can be
a rechargeable battery (such as coil cells) according to application demands. The following figure shows a
reference design for powering RTC with an external battery.
VRTC
RTC
Core
Coin Cell
Module
Figure 10: RTC Powered by Coin Cell
If RTC is ineffective, it can be synchronized through network after the module is powered on.
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When VBAT is disconnected, the input voltage range of VRTC is 2.0–3.25 V with the typical value
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