T-Line Waveforms--End termination is less sensitive to delay balance

(Originally published in EDN Magazine)
 

Sensitivity to balance of trace delays Now we will see what goes wrong with the source-termination if the trace lengths are not the same. Use the same setup as before, with a 50-ohm source termination, but now we will modify the lengths of segments B-C and B-D. Set segment B-C to .75 ns and segment B-D to 1.25 ns. That’s a difference of 0.500 ns, or 1/2 of a risetime. Only one of the two received signals is shown. This system is pretty sensitive to delay, isn’t it! An end-terminated system is less sensitive to delay balance.

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