Sunsea AIoT SimCom SIM7090G User Manual page 23

SIM7090G User Manual V1.01
Figure 5: Power supply application circuit
In addition, for ESD protection, it is suggested to add a TVS diode near the VBAT PINs. These capacitors
should be put as close as possible to VBAT pads. Also, users should keep VBAT trace on circuit board
wider than 1 mm to minimize PCB trace impedance.
NOTE
1. The customer's circuit design must have the function that the master can control the power off of the
module. The module can be shut down or restarted normally. Only when the module is abnormal and
cannot be shut down or restarted normally can the power be turned off.
2. When the module is working normally, do not cut off the power supply of the module VBAT directly to
avoid damage to the internal flash of the module. It is strongly recommended to turn off the module
through PWRKEY or AT command before disconnecting the module VBAT power.
3.1.2 Voltage Monitor
To monitor the VBAT voltage, the AT command "AT+CBC" can be used.
AT command "AT+CBATCHK=1" can be used to enable the overvoltage warning function and the
under-voltage warning function. The default value of the overvoltage warning function in the software is
4.85V, and the default value of the under-voltage warning function is 2.8V. If the power supply for VBAT pins
is up 4.85V or under 2.8V, module will be warning.
The AT command "AT+CBATCHK=1" also can be used to enable the overvoltage power-off function and the
under-voltage power-off function. The default value of the overvoltage power-off function is 4.9V, and the
default value of the under-voltage power-off function is 2.5V. If the VBAT voltage is up 4.9V or under 2.5V,
module will be power off.
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