Sim800 hardware design v1.05

Smart Machine Smart Decision
SIM800_Hardware Design_V1.05 22 2014-03-25
T
e
input voltage never drop below 3.0V even when current consumption rises to 2A in the transmit burst. If the
power voltage drops below 3.0V, the module may be shut down automatically. The PCB traces from the VBA
pins to the power supply must be wide enough (at least 60mil) to decrease voltage drops in the transmit burst. Th
power IC and the bypass capacitor should be placed to the module as close as possible.
Figure 9: The minimal VBAT voltage requirement at VBAT drop
.1.2. Monitoring Power Supply
he AT command “AT+CBC” can be used to monitor the VBAT voltage. For details please refer to document
.2. Power on/down SIM800
.2.1. Power on SIM800
ser can power on SIM800 by pulling down the PWRKEY pin at least 1 second and then release. This pin is
4
T
[1].
4
4
U
already pulled up to VBAT in the module internal, so external pull up is not necessary. Reference circuit is shown
as below.
Figure 10: Power on/down module using transistor