What Is a LVDS Transceiver?

LVDS (Low-Voltage Differential Signaling) is a differential signal technology with low power consumption, low bit error rate, low crosstalk, and low radiation. This transmission technology can reach more than 155Mbps. Extremely low voltage swing high-speed differential transmission data can realize point-to-point or point-to-multipoint connection. The transmission medium can be copper PCB connection or balanced cable. ^[1]

LVDS (Low Voltage Differential Signalin) is a low-amplitude differential signal technology. It uses very low amplitude signals (about 350mV) to transmit data through a pair of differential PCB traces or balanced cables. It can transfer serial data at speeds of up to thousands of Mbps. Because the amplitude of the voltage signal is low and

With the continuous advancement of electronic design technology, the interconnection of high-speed signals and the application of broadband channels are increasing day by day, and the amount of data to be transmitted is getting larger and faster. Currently, there are point-to-point physical layer interfaces such as

The basic working principle of LVDS is shown in Figure 1.

The reason why LVDS has become the preferred signal form of the current high-speed I / O interface to solve the limitation of high-speed data transmission is because it has advantages in terms of transmission speed, power consumption, anti-noise, and EMI.

High-speed transmission capability. The LVDS standard in the ANS / EIA / EIA-64 definition has a theoretical limit rate of 1.923Gbps. The constant-current source mode and low-swing output operating mode determine that the IVDS has high-speed drive capabilities.

Low power consumption. LVDS devices are implemented using CMOS technology, and (MOS can provide lower static power consumption; when the driving current of the constant current source is 3.5mA, the power consumption of the load (100 terminal matching) is only 1.225mW; the power consumption of LVDS Is constant, unlike (

In the field of radar applications, with the development of technology, the emergence and popularization of new system radars such as DBF system radars and phased array radars, the signal bandwidth and number of signal channels to be processed have increased significantly, and they are facing the transmission of large amounts of data. problem. Therefore, the new technology adopted to solve the I / O interface problem has become an inevitable trend. LVDS, a high-speed and low-power interface standard, makes it possible to solve this transmission bottleneck problem. Therefore, the current LVDS technology is widely used in high-speed radar and high-speed receiving systems; LVDS technology is used to achieve point-to-point single-board interconnection, and the system architecture is very scalable, achieving high integration of line cards and various subsystems, and completely Can meet the requirements of data collection and transmission.

In terms of civilian use, this technology can support high-speed data transmission and is most suitable for communication structure application solutions such as base stations, switches, add / subtract multiplexers, consumer product application solutions such as set-top boxes and home / enterprise video links, and medical applications. Ultrasound imaging equipment and digital photocopiers ensure greater flexibility in system partitioning operations. System design engineers can use LVDS technology to place analog and digital signal processing sections on different circuit boards, and then use cables or backplanes to transmit digital data output by the A / D converter to ensure greater flexibility in the structural design. At present, basically all kinds of high-speed AD converters choose to use the LVDS signal as the output format of the sampling data, and their output forms are mostly parallel outputs. At the same time, special chips supporting IWDS and other level interchange and special chips for LVDS speed reduction are also emerging, mainly represented by several foreign companies such as MAXM, NI and TI.

In addition, LVDS has a very wide application space in high-speed data transmission of measurement and control systems, SAR radar reconnaissance reception and high-speed digital image transmission applications. Especially in recent years and the next few years, the aerospace, military, communications and other departments' demands for flexible high-rate communication systems continue to grow. On the one hand, the core of traditional communication systems, such as filters and mixers, are mostly implemented using analog devices, which are greatly restricted in terms of system reliability, flexibility, upgrade and maintenance, etc. In the past 20 years, the rapid development of microelectronics technology, integrated circuits, and digital communication theories has provided the possibility of using digital methods to achieve many links in high-bit-rate communication systems. According to the data obtained so far, a number of all-digital high-bitrate baseband signal processors with excellent performance and flexibility have been successfully developed abroad. Against this background, as a unit devoted to the development of China's military electronic technology, especially focusing on the research and development of related technologies and products in the field of aerospace measurement and control, at present, we have been in the research process of high bit rate digital transmission technology Major breakthroughs have been made in the field, and one of the key technologies applied is LVDS technology ^[2] .