Monitoring Power Supply; Power On/Down Scenarios; Power On Sim800C - SIM Tech SIMCom SIM800C Hardware Design

VBAT
MIN:3.0V
Figure 9: The minimal VBAT voltage requirement at VBAT drop
Note: Hardware power down voltage is 3.0V.
4.1.2.

Monitoring Power Supply

AT command "AT+CBC" can be used to monitor the VBAT voltage. For detail, please refer to document [1].

4.2. Power on/down Scenarios

4.2.1.

Power on SIM800C

Customer can power on SIM800C by pulling down the PWRKEY pin for at least 1 second and release. This pin
is already pulled up to VBAT in the module internal, so external pull up is not necessary. Reference circuit is
shown as below.
Turn on/off
impulse
The power on timing is illustrated as in the following figure.
SIM800C_Hardware_Design_V1.00
PWRKEY
4.7K
47K
Figure 10: Powered on/down module using transistor
PWRKEY
Figure 11: Powered on/down module using button
VBAT
R
Power
on/down logic
1K
Module
VBAT
R
Power
on/down logic
1K
Module
19
Smart Machine Smart Decision
2014-10-30