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MeiG Smart product technical information
SLM500 Hardware Design Guide Page 29
3. 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 4.1：VBAT input reference circuit