I understand that for single ended RF signals I must ensure that the characteristic impedance of the transmission line matches the load impedance (say 50 ohm). I am a bit confused for differential RF signals though. Do I try and match the differential impedance to 100 ohm and the characteristic impedance to 50 ohm simultaneously?

Clarification would be appreciated



1 Answer 1


Usually this means creating two 50Ω lines that form a differential pair. Because both pairs are also used differential they are coupled to each other so you need to calculate the impedance stackup and width for a 100Ω edge coupled external line. If it's internal on a PCB, you'll need the height between both layers. Use a tool like saturn PCB tool to calculate (diff pairs tab).

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