Differential pair

From Wikipedia, the free encyclopedia

Differential pair is a pair of conductors with special characteristics, used for differential signaling.

Examples of the differential pair include:

twisted-pair cables, shielded and unshielded
microstrip and stripline differential pair routing techniques on printed circuit boards

Differential pairs are usually found on a printed circuit board, in cables (twisted-pair cables, ribbon cables), and in connectors.

Differential pair can be considered as a PCB implementation of a well-known twisted-pair cable. However, from the modern point of view, twisted-pair is nothing but particular implementation of a differential pair.

Differential pairs are generally used to:

Carry differential or semi-differential signals, such as
- High-speed digital serial interfaces including LVDS, SATA, Hypertransport, Ethernet, Serial Digital Interface, etc.)
- High quality and/or high frequency analog signals (e.g. video signals, professional audio signals, etc.)
Minimize cross-talk and electromagnetic interference, both noise emission and noise acceptance by the signal carried by differential pair
Achieve constant and/or known characteristic impedance, which is important in high-speed signal transmission, to use impedance matching techniques