MeiG_SLM550_Hardware Design Manual
MeiG Smart Technology Co., Ltd
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4 Interface application
4.1 Power Supply
In the case of a battery device, the voltage input range of the module VBAT is 3.4V to 4.2V, and the
recommended voltage is 3.8V. In the GSM band, when the module is transmitting at maximum power,
the peak current can reach up to 3A, resulting in a large voltage drop on VBAT.
It is recommended to use a large capacitor regulator close to VBAT. It is recommended to use two 47uF
ceramic capacitors. Parallel 33PF and 10PF capacitors can effectively remove high frequency
interference. To prevent damage to the chip due to ESD and surge, it is recommended to use a suitable
TVS tube and a 5.1V/500mW Zener diode at the VBAT pin of the module. For PCB layout, the
capacitors and diodes should be as close as possible to the VBAT pin of the module. The user can
directly power the module with a 3.7V lithium-ion battery. When using the battery, the impedance
between the VBAT pin and the battery should be less than 150mΩ.
Figure 8 VBAT input reference circuit
If it is a DC power supply device, the DC input voltage is +5V. The recommended circuit that can be
powered by DC-DC is shown below:
Figure 9 DC-DC power supply circuit