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 88
6 Design Guideline
This chapter provides the general design guidance of the product, users can refer to the design
guidance for design, so that the product to achieve better performance.
6.1 General Design rules and requirements
When designing the peripheral circuit of this product, the user must first ensure that the external
power supply circuit can provide sufficient power supply capacity and control the differential
impedance of 90 ohm ± 10% for the high-speed signal line USB. For the general signal interface,
users are required to design strictly in accordance with our requirements, in line with the interface
signal level matching, in case of inconsistent level damage module. The product has good RF
performance, customers need to design the side antenna circuit and do the corresponding
impedance control, otherwise it will affect the RF performance of the whole machine.
6.2 Circuit reference design
It is required that the power supply capacity of VBAT on the board side of the system should be more
than 2A to meet the peak current demand of the module, and the mean current of the power supply
on the system side should be more than 0.9 a. The power supply line on the board side of the system
should have enough line width and form a good return current with the ground plane. In addition, the
100-micrometer energy storage capacitor should be added in the design of the power supply circuit to
ensure the instantaneous power supply, and the power supply ripple should be controlled within 100
MV, detailed functional modules see the corresponding functional description, the overall reference
circuit details see "L508 Design" .
6.3 RF circuit design
6.3.1 Matters needing attention in the initial stage of antenna design