Definition

A differential pair consists of two traces carrying complementary signals (equal magnitude, opposite polarity). The receiver responds to the voltage difference between the two traces, rejecting common-mode noise that affects both equally. Differential signaling is standard for high-speed interfaces (USB, HDMI, Ethernet, PCIe). Critical design parameters include differential impedance (typically 90-100Ω), intra-pair spacing, length matching (skew <10% of bit period), and maintaining constant spacing through the route.