This is a calculator for the characteristic impedance of surface wiring.
For high-speed signals, surface mount wiring with low effective dielectric constant (i.e., low loss and delay) is recommended.
Single 50Ω: DDR data bus, DDR address bus
Differential 75Ω: Analog video signal
Differential 85Ω: USB, PCI Express
Differential 90Ω: DDR DQS, DDR clock
Differential 100Ω: Ether, MDII, LVDS, MIPI