Modeling and Fast Eye Diagram Estimation of Ringing Effects on Branch Line Structures

Significant ringing effects due to multiple reflections are first addressed for the slightly unbalanced address lines in the double data rate memory systems. A resistance-inductance-capacitance resonance model is proposed to explain its occurrence by fitting the transfer function in frequency domain. The transient analysis can then be performed easily and the peak distortion analysis is used to predict its eye height. The cases with the worst signal integrity were identified and a simple design rule is derived to avoid its occurrence, which is dependent on the attenuation constant of the transmission line and the data rate of the signal.