Views: 0 Author: Site Editor Publish Time: 2023-10-30 Origin: Site
The communication line lightning protection is installed on the PCB in series. Therefore, when selecting lightning protection devices, it is necessary to ensure that the lightning protection devices can play a protective role, and at the same time, the matching problem of the lightning protection devices and communication lines must also be considered. Therefore, the following three points should be mainly considered when selecting lightning protection devices:
1
Voltage level problem
2
Rate matching problem
3
Device installation issues
Lightning protection is becoming more and more important for highly integrated and sophisticated electronic equipment and data transmission. Yint Electronic Devices can provide comprehensive lightning protection solutions. In order to illustrate different practical applications, the actual protection is divided into three categories:
Basic protection level
Designed according to IEC61644-1 (Draft1997), it is used to discharge lightning current and is the first level of protection. It is installed at the cable entry point.
Comprehensive protection level
According to Class1+2+3 of IEC61644-21, as a sophisticated comprehensive protection, it can be designed directly at the front end of the equipment information input (such as the equipment is close to the cable entry point)
It is mainly used to limit surge overvoltage. The distance from the basic protection level should be no less than 5m, and it is designed directly at the access end of the access chip or sensitive devices such as DSP and ARM.
Environmental analysis of actual product use
A) Is the product placed outdoors?
Will there be any overhead introduction at the upper end?
Voltage level selection
B) The selection of the maximum working voltage of communication equipment is determined based on the working voltage of communication. The working voltage of the protection device must be greater than 1.2 to 1.414 times the working voltage of the communication line on the equipment.
Rate matching options
C) Communication line lightning protection is designed on the equipment line. The maximum transmission rate it supports should be greater than the transmission rate of the communication line. Otherwise, it will cause communication interruption or increase in bit error rate, packet loss, and data loss, which is usually reflected in the device capacitance.
Relevant standards suitable for product equipment
D) Communication products have different requirements in different countries. In addition, there is a relevant standard level that the product wants to reach.
Device size and installation location
E) Consider the size of the device, whether the PCB is easy to install, whether the installation location is close to a heat source or other harsh conditions, whether high-frequency vibration is required, etc.
The selection of the highest working voltage of the protection device on the communication line is determined based on the working voltage of the data communication line. It is an important parameter for selecting protection devices, but there is no common standard in practical applications. The working voltage of the protection device should be greater than the line communication voltage. (Attached is the working voltage of commonly used communication lines, for reference only, there are still differences between different chip manufacturers)
Communication line type | video cable | RS422RS485 | RS232 | Ethernet over Coax | 100M Ethernet | Analog telephone line/ADSL | 2M digital relay | XDSL | DDNX 25/frame relay | ISDN |
Rated work Voltage(V) | <6 | <5 | <12 | <5 | <5 | <90 | <5 or<12 | <6 | <6 or <40~60 | <40 |
General rate BPS |
| 2M |
| 10M | 100M | <2M | 2M | 8M | 2M | 2M |
Lightning protection device Operating Voltage | 6.5 | 6 | 18 | 6.5 | 6.5 | 180 | <6.5or<18 | 18 | 18 or 80V | 80 |
Interface Type | BNC | ASP/SD | SD | RJ | RJ | RJ | BNC RJ45 | ASP RJ45 | ASP RJ45 | RJ |
GB50057-1994 | Design Code for Lightning Protection of Buildings |
GB50343-2004 | Technical specifications for lightning protection of building electronic information systems |
YD5098-2005 | Design specifications for lightning protection and grounding engineering of communications bureaus (stations) |
YD/T1235.1/2002 | Technical requirements for surge protectors for low-voltage power distribution systems in communications bureaus (stations) |
YD/T1235.2/2002 | Test method for surge protectors used in low-voltage power distribution systems of communications bureaus (stations) |
DL548-94 | Lightning protection operation and management regulations for power system communication stations |
GA173-2002 | Computer information system lightning protection security device |
GA267-2000 | Safety Protection Specification for Lightning Electromagnetic Pulse in Computer Information Systems |
TB/T3074-2003 | Technical conditions for lightning electromagnetic pulse protection of railway signaling equipment |
TB/T 2311-2002 | Lightning protector for railway electronic equipment |
YD/T993-2006 | Lightning protection technical requirements and experimental methods for telecommunications terminal equipment |
