Installation Instructions

Table Of Contents
L508 Hardware Design
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better transient current response, meet the working requirement of the module under the weak signal
of 2G, and prevent the network drop or port restart caused by power shortage.
LM2596-ADJ
IN
EN
GND
FB
OUT
DC_IN
MCU_GPIO
100uF 1uF
2.2K
1K
VBAT
330uF
100nF
100uH
MB R3 60
Figure 10 Recommended DC/DC power supply circuit
4.4.4 Charging circuit design reference
The module has reserved the charging interface. If you want to realize the charging function, you can
refer to the following charging circuit
Table 15 Charging interface definition
Pin No. Pin Name I/O Functional description
11 USB_VBUS PI USB power detect
15 VDD1V8 PO LDO for I/O
45 GPIO_20 B_PD Charging chip enable, active low
46 ADC2 AI Battery NTC temperature detection
47 ADC1 AI Battery voltage detection
84 GPIO_05 B_PU Charging state detection
86 EXTON1N AI Charging startup detection, charging module startup