Specifications

Smart Machine Smart Decision
SIM7080G _Hardware Design _V1.03 24 2019-12-13
3.2 Power on/Power off Function
3.2.1 Power on
SIM7080G can be powered on bybriefly pulling the PWRKEY pin to ground.
The PWRKEY pin has been pulled up with a diode to 1.8V internally, so it does not need to be
pulled up externally. It is strongly recommended to putan ESD protection diode close to the
PWRKEY pin, as it would strongly enhance the ESD performance of PWRKEY pin.
The PWRKEY pin has its own reset function. The reset time is determined by the internal timer
(default is 15 seconds). After the PWRKEY is pulled low, the module will be reset after 15 seconds.
Therefore, it is not recommended to connect PWRKEY to GND all the time in external circuit
design.
Please refer to the following figure for the recommended reference circuit.
4.7K
47K
Turn on / off
impulse
PWRKEY
Power
On/off logic
Vdd
MODULE
1K Ω
The high voltage of PWRKEY is
1.5V
1.5V
0V
Figure 8: Reference power on/off circuit
The power-on scenarios are illustrated in the following figure.
STATUS
( Output)
T
on
VBAT
PWRKEY
( Input)
UART Port
Undefined
active
T
on( uart
)
Undefined
active
USB Port T
on
(
usb
)
Ton( VDD)
VDD_ EXT
( Output)
T
on(status
)
Figure 9: Power on timing sequence