Systematic Lumped-Element Modeling of Differential IC Transmission Lines

In this paper, we report a systematic and efficient approach to obtain lumped-element models for differential integrated-circuit interconnect transmission lines covering both the low-frequency R/C as well as the high-frequency quasi-TEM behavior. To accurately model signal delay and loss, and to preserve causality, the frequency dependence of both line resistance as well as the line inductance is included in our model. The impact of ground inductance is also properly covered by the model. The validity of our approach is verified against experimental data collected up to 120 GHz for the even and odd modes on these differential transmission lines. We predict that these lines can transport data over 1-cm distance with rates up to 40 Gb/s, even with some imbalance in differential drive.