Voltage Monitor; Power On/Power Off/Reset Function; Power On - SimCom SIM7020C Hardware Design

Module
In addition, for ESD protection, it is suggested to add a TVS diodenear the VBAT PINs.
Table 7: Recommended TVS diode list
No. Manufacturer
1 Prisemi
2 Prisemi
3 WILLsemi
3.3

Voltage Monitor

To monitor the VBAT voltage, the AT command "AT+CBC" can be used.
When the VBAT voltage is out of the range, the module will be power off when the overvoltage
power-off function is enabled. The AT command "AT+CBATCHK=1" can be used to enable the
overvoltage power-off function and the under-voltage power-off function.
Note: Under-voltage warning function and under-voltage power-off function are disabled by
default. For more information about these AT commands, please refer to Document [1].
3.4

Power on/Power off/Reset Function

3.4.1

Power on

SIM7020 can be powered on by pulling the PWRKEY pin to ground.
The PWRKEY pin has been pulled up with a resistance to VBAT internally, so it does not need to
be pulled up externally. It is strongly recommended to put a 100nF capacitor and an ESD protection
diode close to the PWRKEY pin, as it would strongly enhance the ESD performance of PWRKEY
pin. Please refer to the following figure for the recommended reference circuit.
SIM7020_Hardware_Design_V1.02
VBAT
Ce Cd
VBAT
1uF
100nF
GND
GND
Figure 5: Power supply application circuit
Part Number
PESDHC2FD4V5B
PESDHC3D3V3U
ESD5651N-2/TR
17
Smart Machine Smart Decision
Ca
Cc
Cb
100uC
100uF
100uF
Package
DFN1006
SOD323
DFN1006
VBAT
5.1V
500mW
2018-07-25