Installation Instructions
Table Of Contents
- Contents
- List of Table
- List of Figures
- 1 About this document
- 2 Product Overview
- 3 Mechanical Dimensions
- 4 Interface description
- 4.1 Pin Definition
- 4.2 Operating conditions
- 4.3 Digital logic characteristics
- 4.4 Power interface
- 4.5 USIM card interface
- 4.6 PCM interface
- 4.7 USB2.0 interface
- 4.8 UART interface
- 4.9 SPI interface
- 4.10 I2C interface
- 4.11 Network light
- 4.12 System Status Indication
- 4.13 Flight Mode
- 4.14 Forced USB download interface
- 4.15 SD card interface
- 4.16 SDIO_WIFI/EMMC interface
- 4.17 PCIe interface
- 4.18 RMII/RGMII interface
- 4.19 AUDIO interface
- 4.20 ADC
- 4.21 GPIOs
- 4.22 Power on/off and reset interface
- 4.23 Antenna interface
- 5 Product characteristics
- 6 Design Guideline
- 7 Storage, Production and Package
- 8 Safety Information
- 空白页面
- 空白页面
L508 Hardware Design
Copyright© Shanghai Mobiletek Communication Ltd 38
1 On semi MMSZ5231BT1G 500mW SOD123
2 Prisemi PZ3D4V2H 500mW SOD323
3 Vishay MMSZ4689-V 500mW SOD123
4 Crownpo CDZ55C5V1SM 500mW 0805
4.4.3 Power Supply Design Guide
If the voltage difference is not big, can use "power supply scheme". LDO requires over-current
capacity of more than 2A, but because LDO is a linear buck, its transient response capacity is poor,
and the front and rear terminals need to be equipped with a large amount of capacitance, to prevent
GSM high-power transmission when the voltage fluctuation is too large, may lead to reset or
shutdown. Output voltage to be controlled at 3.8V.
MIC29302WU
IN
EN
GND
ADJ
OUT
51K
47K
47K
DC_IN
MCU_GPIO
300uF 100nF
100K
47K
470R
VBAT
1%
1%
300uF
100nF
Figure 9 Recommended LDO power supply circuit
If the voltage difference is large, it is recommended to use DC/DC, the output current requirements of
more than 2A, such as figure 4-5 using DC switching power supply, supplemented by a large capacity
(more than 330 UF) , to ensure the normal operation of RF PA (power amplifier) , provides sufficient
transient current in GSM Burst mode. The advantage of the reference design is that it can provide