Tutorial on Microstrip and Stripline Design

Much has been written about terminating PCB traces in their characteristic impedance, to avoid signal reflections. However, it may not be clear when transmission line techniques are appropriate. A good guideline to determine when the transmission line approach is necessary for logic signals is to terminate the transmission line in its characteristic impedance when the one-way propagation delay of the PCB track is equal to or greater than one-half the applied signal rise/fall time (whichever edge is faster). This tutorial goes over how to design controlled impedance transmission line traces on PCB's. Multiple configurations are discussed.