Product Info

Smart LTE Module Series
SC20 Hardware Design
SC20_Hardware_Design 38 / 130
1. It is suggested that customers should switch off the power supply for module in abnormal state, and
then switch on the power to restart the module.
2. The module supports battery charging function by default. If the above power supply design is
adopted, please make sure the charging function is disabled by software or connect VBAT to
Schottky diode in series to avoid the reverse current to the power supply chip.
3.5. Turn on and off Scenarios
3.5.1. Turn on Module Using the PWRKEY
The module can be turned on by driving PWRKEY pin to a low level for at least 1.6s. PWRKEY pin is
pulled to 1.8V internally. It is recommended to use an open drain/collector driver to control the PWRKEY.
A simple reference circuit is illustrated in the following figure.
Turn on pulse
PWRKEY
4.7K
47K
≥ 1.6s
R1
R2
Q1
Figure 6: Turn on the Module Using Driving Circuit
The other way to control the PWRKEY is using a button directly. A TVS component is indispensable to be
placed nearby the button for ESD protection. A reference circuit is shown in the following figure.
NOTES