Transient simulation of lossy multiconductor interconnects

The transient simulation of electrically-long low-loss multiconductor interconnects is considered from a practical point of view. The importance of frequency dependent losses in these interconnects is discussed and a simple transmission line characterization procedure allowing for such losses is proposed. The characterization obtained yields simple and efficient interconnect models, that the user can include, without programming, in any simulator accepting differential operator

Lossy transmission line response via numerical Laplace transform inversion

An efficient transient analysis of lossy lines with nonlinear loads requires the ability to compute and represent a suitable set of line impulse responses. In this paper, we propose the evaluation of the matched-line impulse responses by means of an algorithm for the numerical inversion of the Laplace transform. Based on a discussion of the structure of the impulse responses, we demonstrate how, for this class of functions, the method proposed is particularly effective and convenient, in comparison with the conventional FFT approach. We also compare the line responses due to the exact per-unit-length resistance of a circular wire with those due to a simplified model, and find a non-negligible influence on the integrity of the signals that propagate on the lin

Behavioral models of digital IC ports from measured transient waveforms

This paper addresses the behavioral modeling of output ports of digital integrated circuits via the identification of nonlinear parametric models. The aim of the approach is to produce models for signal integrity (SI) simulation directly from the measured transient responses of the devices. The modeling process is thoroughly described and an experimental demonstration of its feasibility is give

The Role of Probe Attenuation in the Time-Domain Reflectometry Characterization of Dielectrics

The influence of the measurement setup on the estimation of dielectric permittivity spectra from time-domain reflectometry (TDR) responses is investigated. The analysis is based on a simplified model of the TDR measurement setup, where an ideal voltage step is applied to an ideal transmission line that models the probe. The main result of this analysis is that the propagation in the probe has an inherent band limiting effect, and the estimation of the high-frequency permittivity parameters is well conditioned only if the wave attenuation for a round trip propagation in the dielectric sample is small. This is a general result, holding for most permittivity model and estimation scheme. It has been verified on real estimation problems by estimating the permittivity of liquid dielectrics and soil samples via an high-order model of the TDR setup and a parametric inversion approac

Analysis of crosstalk and field coupling to lossy MTL's in a SPICE environment

This paper proposes a circuit model for lossy multiconductor transmission lines (MTLs) suitable for implementation in modern SPICE simulators, as well as in any simulator supporting differential operators. The model includes the effects of a uniform or nonuniform disturbing field illuminating the line and is especially devised for the transient simulation of electrically long wideband interconnects with frequency dependent per-unit-length parameters. The MTL is characterized by its transient matched scattering responses, which are computed including both dc and skin losses by means of a specific algorithm for the inversion of the Laplace transform. The line characteristics are then represented in terms of differential operators and ideal delays to improve the numerical efficiency and to simplify the coding of the model in existing simulators. The model can be successfully applied to many kinds of interconnects ranging from micrometric high-resistivity metallizations to low-loss PCBs and cables, and can be considered a practical extension of the widely appreciated lossless MTL SPICE model, which maintains the simplicity and efficienc

Scattering analysis of signal degradation and interferences on long and lossy interconnects

A time domain scattering formulation for low-loss nonlinearly loaded multiconductor transmission lines is presented. It is suitable for an efficient and accurate evaluation of crosstalk and field coupling. A simulation of the effects of interference on a long interconnect is give

Influence of the line characterization on the transient analysis of nonlinearly loaded lossy transmission lines

The analysis of nonlinearly terminated lossy transmission lines is addressed in this paper with a modified version of a method belonging to the class of mixed techniques, which characterize the line in the frequency domain and solve the nonlinear problem in the time domain via a convolution operation. This formulation is based on voltage wave variables defined in the load sections. The physical meaning of such quantities helps to explain the transient scattering process in the line and allows us to discover the importance (so far often overlooked) of the reference impedance used to define the scattering parameters. The complexity of the transient impulse responses, the efficiency of the algorithms, and the precision of the results are shown to be substantially conditioned by the choice of the reference impedance. The optimum value of the reference impedance depends on the amount of line losses. We show that a low-loss line can be effectively described if its characteristic impedance or the characteristic impedance of the associated LC line is chosen as the reference impedance. Based on the physical interpretation of our formulation, we are able to validate the numerical results, and to demonstrate that, despite claimed differences or improvements, the formulations of several mixed methods are fundamentally equivalen