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Low voltage differential signaling (LVDS) is a way to communicate data using a small voltage-swing (about 350 mV) differential signal, over a backplane, on a pc board or across cable. It offers very high rates-gigabit/second speeds-at very low power, and is therefore the interface technology of choice in many systems. LvDS has been standardized as ANSI/EIA/TIA-644 and is supported by semiconductor vendors.
The differential data transmission method used in LVDS is less susceptible to commonmode noise than single-ended schemes. Dif ferential transmission uses two wires with opposite current/voltage swings instead of the one wire used in single-ended methods to convey data information. The advantage of the differential approach is that noise is coupled onto the two wires as common-mode (the noise appears on both lines equally) and is thus rejected by the receivers, which look at only the difference between the two signals. The differential signals also tend to radiate less noise than single-ended signals due to the canceling of magnetic fields. And, the current-mode driver is not prone to ringing and switching spikes, further reducing noise.
Because differential technologies such as LVDS reduce concerns about noise, they can use lower signal voltage swings. This advantage is crucial, because it is impossible to raise data rates and lower power consumption without using low-voltage swings. The low-swing nature of the driver means data can be switched very quickly. Since the driver is also current-mode, very low-almost flat-power consumption across...