Smart Module Series
SC690A_Series_Hardware_Design 41 / 105
The turning on the scenario is illustrated in the following figure.
VBAT(Typ:3.8 V)
PWRKEY
> 1.6 s
Others
LDO9_1V8
38 s
165.4 ms
Software
controlled
LDO5_2V96
Active
Note2
Software
controlled
Figure 9: Timing of Turning on Module
1. When the module is powered on for the first time, its timing of turning on may be different from that
shown above.
2. Ensure that VBAT is stable before pulling down the PWRKEY pin. It is recommended to wait until
VBAT to be stable at 3.8 V for at less 30 ms before pulling down PWRKEY. Additionally, PWRKEY
cannot be pulled down all the time.
3.3. Turn off
Set the PWRKEY pin low for at least 1 s, 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 8 s. The module will
execute the forced shutdown.
The forced power-down scenario is illustrated in the following figure.
NOTE
