UCSC-CRL-95-25: TRANSIENT ANALYSIS OF COUPLED TRANSMISSION LINES CHARACTERIZED WITH FREQUENCY-DEPENDENT LOSSES OR MEASURED SCATTERING-PARAMETER DATA AND OPTIMAL DESIGN OF SELF-DAMPED INTERCONNECTS

06/01/1995 09:00 AM
Computer Engineering
As the packaging density and the clock speed of the multichip modules (MCMs) increase, crosstalk induced noise can become one of the major sources of noise which will limit the performance of the high-speed digital systems. In addition, as the magnitudes of the harmonics of the transmitted signals above $1$ GHz become more significant, the interconnects exhibit more frequency-dependent conductor losses (skin effect) and the dielectric losses (dispersion). In order to design the interconnects more accurately and more efficiently, the S-parameters macromodels of the coupled lossless and lossy transmission lines with frequency-dependent losses are constructed in this thesis. Since the discontinuities in interconnects are hard to describe with close form equations, they are better characterized with measured S-parameter data. Thus, it is equally important to include the measured S-parameter macromodel in the transient analysis. The task of designing interconnections does not stop at viewing simulation waveforms, it requires the design optimization as well. For today\'s Computer-Aided Design tools, it usually takes several iterations between the layout and the simulation tools to find the optimal design of the interconnects. A simple and robust method of designing the lossy-transmission-line interconnects in a network for multichip modules has been developed. It uses wire-sizing to solve the problems encountered in propagating high-speed signals through unterminated lossy transmission lines on the substrates of multichip modules. The optimal self-damped design concept is used to relate the layout parameter (line width) and the transfer function (damping ratio, and natural undamped frequency) to the signal propagation delay. This method can produce a fast and a more stable signal propagation for single-source multi- receiver networks on multichip modules, without using termination resistors. There are further improvements that can be gained by incorporating an incremental simulation and a sensitivity analysis into the optimal design to improve the efficiency. Building these scattering parameter macromodels greatly improves the accuracy and the efficiency of the transient analysis. Together with the optimal design, they provides a faster turn around time in producing high-performance MCM designs. Notes: Ph.D. Thesis

UCSC-CRL-95-25