LVDS stands for Low Voltage Differential Signaling. It is a physical interface that complies with the TIA/EIA-644 electrical standard for serial communications over twisted pair copper cables and printed circuit board (PCB) tracks. It is a physical layer only specification that can be used with a variety of different protocols.

Low Voltage relates to the low signal voltage levels utilized (approximately 350mV) that drive a cable with a characteristic impedance of 100-120 Ohms. Differential signaling systems use complimentary signals on a pair of conductors. When an AC signal is sent down one of the wires, the same signal, 180^o out of phase is returned to the source. The information sent is encoded in the difference signal between conductors. This arrangement is said to be balanced. This reduces electromagnetic interference and crosstalk of signals and leads to improved performance. Balanced conductors used for LVDS are twisted pairs in cables and transmission lines implemented as coupled microstrip on PCBs.

The twisted pair of conductors creates a tight electric and magnetic field between the two wires. External noise will couple into both conductors equally, and cancel each other in the receiver, referred to as common mode noise. Since LVDS is low power (<10mW) and constant current, it lowers the performance requirements of the power supply. The low common mode voltage – the center voltage of the signaling on the two lines is around 1.2V which makes it compatible with a range of digital integrated circuit technologies. LVDS interfaces are integrated directly with many integrated circuits, and can be found to operate up to 655Mbits/S over 10 meters of cable. Higher frequencies tend to use current mode transceiver based standards.

LVDS was first introduced in 1994 and is still widely used today for providing interfacing between high-speed systems like LCD displays and computer buses. It is a popular interface for signals that need to be distributed with low-noise objects such as clocks. LVDS can operate potentially over up to 10 meters of cable High-Speed LVDS transceivers have equalization circuits that adjust the shape of the signal with frequency to compensate for losses. This can enable LVDS on PCB and system back planes up to 3.125Gbits/S.