SIM340 Hardware Design
Max:400mV
VBAT
Burst:2A
I
VBAT
4.615ms
577us
Figure
6: VBAT voltage drop during transmit burst
3.3.1 Power supply pins on the board-to-board connector
Eight VBAT pins of the board-to-board connector are dedicated to connect the supply voltage; six
GND pins are recommended for grounding. VRTC pin can be used to back up the RTC.
3.3.2 Minimizing power losses
Please pay special attention to the supply power when you are designing your applications. Please
make sure that the input voltage will never drop below 3.4V even in a transmitting burst during
which the current consumption may rise up to 2A. If the power voltage drops below 3.4V, the
module may be switched off. The PCB traces from the VBAT pins of connector to the power
source must be wide enough to ensure no voltage drops occur in the transmitting burst mode.
3.3.3 Monitoring power supply
To monitor the supply voltage, you can use the “AT+CBC” command which include three
parameters: charging status, voltage percent and voltage value (in mV). It returns the battery
voltage 1-100 percent of capacity and actual value measured at VBAT and GND.
The voltage is continuously measured at intervals depending on the operating mode. The
displayed voltage (in mV) is averaged over the last measuring period before the AT+CBC
command is executed.
For details please refer to
document [1]
3.4 Power up and power down scenarios
3.4.1 Turn on SIM340
SIM340 can be turned on by various ways, which are described in following chapters:
Via PWRKEY pin: starts normal operating mode
(please refer to chapter 3.4.1.1)
;
SIM340_HD_V3.09
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