LVDS Cable Delivers Higher Bit Rates, Lower Power, and Improved Noise Performance Due to the Internet’s tremendous growth.
Data transfers are increasing dramatically in all areas of communications. In addition, data streams for digital video, HDTV, and color graphics are requiring higher and higher bandwidth.
What is Low-Voltage Differential Signaling (LVDS)?
The digital communications deluge is the driving force for high-speed interconnects between chips, functional boards, and systems.
The information may be digital, but it is analog Low Voltage Differential Signaling (LVDS) that designers choose to drive these high-speed broadcast lines.
LVDS’s established speed, low power, noise control. And cost advantages are popular in point-to-point applications for communications, data communications, and displays.
LVDS customs high-speed analog circuit techniques to provide multi-gigabit data transfers on copper interconnects.
Anywhere you need high-speed data transfer (100 Mb/s and higher). LVDS offers a solution. Here are many applications in many market segments that use LVDS for data transmission.
- Low-voltage difference signaling is a generic interface standard for high-speed data transmission. The ANSI/TIA/EIA-644-1995 standard specifies the physical layer as an electronic interface.
- This standard defines driver and receiver electrical characteristics only. It does not specify a protocol, interconnect. Or connector details because these details are application-specific.
- The LVDS Standard’s Working Group chose to define only the electrical characteristics to ensure that LVDS becomes a multipurpose interface standard.
- Therefore, each application that uses LVDS should also reference the appropriate protocol and interconnect standard.
Multiple Technologies and Supply Voltages:
- When choosing the signal-level voltages for drivers and receivers, the standards committee considered LVDS implementation in technologies such as Bipolar, BiCMOS, CMOS, and even GaAs.
- In addition, the working group targeted a wide range of power supplies (such as 5 V, 3.3 V, and 2.5 V) for implementing.
- LVDS to ensure that LVDS would be the interface of choice for future generations of products.
- Low-voltage signals have many advantages, including fast bit rates, lower power, and better noise performance.
- Design engineers have previously used full-swing CMOS and LVTTL (low voltage transistor-transistor logic), but as bit rates upsurge, these solutions become unattractive.
- Recently, designers have turned to reduced-swing technologies such as SSTL and GTL to gain speed, save power, and reduce noise. LVDS increases these compensations by lowering voltage swings to about 300 mV.
- To upsurge noise immunity and noise margins even further, LVDS uses different data transmission. Difference signals are immune to common-mode noise.
- The primary source of system noise. Because its voltage change between logic states is only 300 mV, LVDS can change conditions very fast.
- An appraisal of bus topology helps understand the development of Bus LVDS (BLVDS), the first offspring of LVDS.
- The top two buses in figure 7 show multidrop configurations. The full design is unidirectional because there is a single driver at one end of the bus.
- This simple multidrop bus requires only a single termination on the opposite end of the bus from the driver to stop reflections of the driven signal.
- The apiece of the attached receivers reduces the loaded bus impedance. The loading amount depends on the connector, vias, packaging, and receiver input capacitance.
- If these issues are well designed to keep the loading small, plain LVDS can drive this configuration.
How is LVDS in Low-Power Applications?
- LVDS is also being adapted for very low-power applications, such as a remote base station contingent on the wind- or sun-generated power.
- It is ground-referenced LVDS (GLVDS), which is a proposed standard interface. The JEDEC JC-16 committee for low-voltage interface standards is considering the measure.
- The proposed standard has transmitter output voltages between 0 V and 0.5 V and receiver input sensitivity of at least 100 mV.
- The very low transmitter output voltage delivers for low power consumption by the interface. This lower power consumption is a benefit this technology brings to the LVDS family of standards.