differential pairs (definition)

Differential pairs are identical to LVDS (Low Voltage Differential Signals) and LVPECL signals. Some devices incorporate differential signaling. Two pins are utilized for these signals to be connected to the device. These are known as differential pin pairs. Each differential pin pair has a positive (P) and a negative (N) pin. I/O pins for differential signals can either be synchronous or asynchronous, input or output. The pin pairs can be used for synchronous input and output signals as well as asynchronous input signals. However, only some of the differential pairs can be used for asynchronous output signals. Differential signals require the pins of a pair to switch almost simultaneously. If the signals driving the pins are from IOB flip-flops, they are synchronous. If the signals driving the pins are from internal logic, they are asynchronous.