Dharmendra Saraswat

A fast algorithm and practical considerations for passive macromodeling of measured/simulated data

Passive macromodeling of high-speed package and interconnect modules characterized by simulated/measured data has generated immense interest during the recent years. This paper presents a fast algorithm for generating passive macro-models for simulated/measured data, based on linear formulation. New constraints are proposed to quickly generate passive macromodels. Examples are presented to demonstrate the validity and efficiency of the proposed algorithm.

Global passivity enforcement algorithm for macromodels of interconnect subnetworks characterized by tabulated data

With the continually increasing operating frequencies, complex high-speed interconnect and package modules require characterization based on measured/simulated data. Several algorithms were recently suggested for macromodeling such types of data to enable unified transient analysis in the presence of external network elements. One of the critical issues involved here is the passivity violations associated with the computed macromodel. To address this issue, a new passivity enforcement algorithm is presented in this paper. The proposed method adopts a global approach for passivity enforcement by ensuring that the passivity correction at a certain region does not introduce new passivity violations at other parts of the frequency spectrum. It also provides an error estimate for the response of the passivity corrected macromodel.

Enforcing passivity for rational function based macromodels of tabulated data

With the continually increasing operating frequencies, complex high-speed package and interconnect modules require characterization based on measured/simulated data. Several efficient algorithms were recently suggested for macromodeling of such data to enable transient analysis in the presence of external circuit elements. One of the difficult issues involved here is the passivity violations associated with the computed macromodel. To address this issue, an efficient algorithm is presented in this paper to enforce passivity for macromodels with passivity violations.

Fast Passivity Verification and Enforcement via Reciprocal Systems for Interconnects With Large Order Macromodels

With the ever increasing signal speeds, signal integrity issues of high-speed VLSI designs are presenting increasingly difficult challenges for state-of-the-art modeling and simulation tools. Consequently, characterization and passive macromodeling of high-speed modules such as interconnects, vias, and packages based on tabulated data are becoming important. This paper presents a fast algorithm for passivity verification and enforcement of large order macromodels of scattering parameter based multiport subnetworks. Numerous examples tested on this algorithm demonstrate a significant speed-up compared to the existing algorithms in the literature

Time Domain Delay Extraction-Based Macromodeling Algorithm for Long-Delay Networks

This paper introduces a new time-domain approach for compact macromodeling of multiport high-speed circuits with long delays, characterized by tabulated data. The algorithm is based on partitioning the data in the time-domain and subsequently, approximating each partition via delayed rational functions. This results in a compact low-order macromodel in the form of delayed differential equations, which can be efficiently analyzed in the time-domain using circuit simulators.

Passive reduction algorithm for RLC interconnect circuits with embedded state-space systems (PRESS)

With the increasing operating frequencies and functionality in modern designs, the resulting size of circuit equations of high-frequency interconnect and microwave subnetworks are becoming large. Model-order reduction-based algorithms were recently suggested to handle the solution complexity of such circuits. The major objectives in state-of-the-art model-reduction algorithms are: 1) achieving accurate and compact models; 2) numerically stable and efficient generation of models; and 3) preservation of system properties such as passivity. Algorithms such as PRIMA generate guaranteed passive reduced-order models for large interconnect circuits described by RLC type of circuits. However, with the diverse technologies and complex geometries, it is becoming prevalent to describe some of the embedded linear modules in terms of state-space equations. In this paper, we show how to extend the scope of PRIMA-type first-level reduction algorithms for simultaneous reduction of combined circuits containing both RLC interconnects and embedded modules described by general passive state-space equations, while preserving the passivity of the resulting reduced-order model. Necessary formulation, proof of macromodel passivity, and validation examples are given.

On passivity enforcement for macromodels of S-parameter based tabulated subnetworks

Passive macromodeling of EM subnetworks and high-speed modules characterized by S-parameters has generated immense interest in recent years. The paper presents a comparison of two techniques for the passivity compensation of macromodels of S-parameter based subnetworks. The formulation and implementation of the two techniques are discussed. Numerical examples are presented to validate the theory presented.

Passive macromodels of microwave subnetworks characterized by measured/simulated data

Passive macromodeling of microwave components, high-speed packages and interconnect modules characterized by simulated/measured data has generated immense interest during the recent years. This paper presents an efficient algorithm for addressing the passivity of macromodels from simulated/measured data, based on a linear formulation. Also one of the critical issues involved in such macromodels is the passivity check and compensation. For this purpose, a new theorem and an efficient algorithm are presented. Examples are presented to demonstrate the validity and efficiency of the proposed algorithm.

Passivity Compensation Algorithm for Method-of-Characteristics-Based Multiconductor Transmission Line Interconnect Macromodels

Computation of passive and compact macromodels of distributed interconnects has gained considerable importance during the recent years. Method of characteristics (MoC) is widely used for macromodeling of transmission lines, however, it may not be guaranteed passive. This paper presents a new algorithm for passivity enforcement of MoC-based macromodels of multiconductor transmission lines. The algorithm is based on the first-order perturbation of the related delay differential equations and can handle single as well as coupled interconnects. Necessary theoretical foundations and validating numerical results are presented.

Restoration of passivity in s-parameter data of microwave measurements

Circuit modeling of networks described by tabulated S-parameters has generated immense interest during the recent years. The tabulated data may be obtained either from measurements or full-wave EM simulations. However, one of the major difficulties with such type of data is that, the data can be non-passive in the frequency bandwidth of interest, due to the measurement errors or the numerical errors associated with the full-wave simulator. This causes significant difficulty while interfacing such a data with circuit simulators. To overcome this difficulty, this paper presents an efficient algorithm for restoring the passivity of the S-parameter data, prior to its circuit modeling. Numerical examples are presented to demonstrate the validity and efficiency of the proposed algorithm.