Yu-Shan Li

A Power Plane With Wideband SSN Suppression Using a Multi-Via Electromagnetic Bandgap Structure

In this letter, a power plane with wideband simultaneous switching noise (SSN) suppression using a novel multi-via electromagnetic bandgap (EBG) structure is proposed. The -40dB stopband of the proposed EBG structure is about two to six times wider than the one-via structure, and the relative bandwidth is increased by about two times. It is implemented by only adding some vias between patches and the reference plane without changing any other geometrical parameters from one-via EBG structures. The excellent SSN suppression performance was verified by simulations and measurements

A Double-Surface Electromagnetic Bandgap Structure With One Surface Embedded in Power Plane for Ultra-Wideband SSN Suppression

In this letter, a double-surface electromagnetic bandgap (EBG) structure with one EBG surface embedded in power plane is proposed for ultra-wideband simultaneous switching noise (SSN) suppression in printed circuit boards. The SSN suppression bandwidth is broadened to wider than 30 GHz with a low start frequency by combining traditional EBG structure and the coplanar EBG structure which is embedded in the power plane. Because the coplanar EBG surface is embedded in the power plane, no additional metal layer is introduced by the double-surface EBG structure. Simulations and measurements are performed to verify the broadband SSN suppression, high performance is observed.

Simultaneous Switching Noise Suppression in Printed Circuit Boards Using a Compact 3-D Cascaded Electromagnetic-Bandgap Structure

In this paper, a deep bandgap behavior analysis of the vertical cascaded electromagnetic-bandgap (EBG) structure is made. It is shown that the vertical cascaded EBG structure can be decomposed into two EBG structures cascaded horizontally, one with the bigger patches and the other with the smaller patches. The design guidelines of the vertical cascaded EBG structure are drawn. Furthermore, the vertical cascade concept is extended to 3-D cascade for wideband simultaneous switching noise (SSN) suppression. The number of rows of patches for noise coupling reduction is investigated. Building SSN isolation walls along a printed circuit board for wideband electromagnetic-interference reduction and along sensitive devices for SSN isolation using a 3-D cascaded EBG structure is proposed. Simulations and measurements are performed to verify the SSN suppression. High performance is observed.

Signal Integrity Analysis of the Traces in Electromagnetic-Bandgap Structure in High-Speed Printed Circuit Boards and Packages

In this paper, signal integrity analysis of traces between two parallel planes with an electromagnetic-bandgap (EBG) structure is made. It is shown that, within the stopband, the signal transmission quality is excellent, traces in the EBG structure are free from cavity resonances, and behave as regular standard transmission lines. It is shown that the high-impedance surface behaves as a solid continuous reference plane within the stopband. The impedances of the traces between the high-impedance surface and the reference planes are extracted. It is found that the extracted impedances are exactly the same as striplines with the same parameters. It is shown that the traces between the high-impedance surface and the reference planes are regular standard striplines within the stopband. In addition, a novel four-via EBG structure is proposed to broaden the stopband for simultaneous switching noise suppression in high-speed digital printed circuit boards and packages. This four-via EBG structure has a higher relative bandwidth and lower center frequency. Compared with one-via EBG structure with the same parameters, the stopband is broadened three times and relative bandwidth is increased 1.3 times, while there is very little additional cost since there is no more change than number of vias. Two test boards with four-via EBG structure were fabricated to verify the signal integrity of the traces and the impedances extraction. Good agreements are observed between the simulations and measurements

An Efficient Algebraic Method for the Passivity Enforcement of Macromodels

In this paper, an efficient algebraic method for the passivity enforcement of macromodels is presented. The method is based on quadratic programming with equality constraint. The differences between equality constraint and conventional inequality constraint are discussed. Compared with the general quadratic programming-based method, where the passivity violations are compensated via numerical optimization, the presented method is based on the solution of sparse linear equations. With the special sparse structure of macromodels, the passivity compensation is equivalent to the solution of some small size linear equations. This gives large savings for CPU time and memory requirement. Several examples show that the presented method yields accurate passive macromodels in a limited simulation time.

An Efficient Power-Delivery Method for the Design of the Power Distribution Networks for High-Speed Digital Systems

In this paper, a new power distribution network (PDN) design method from a power delivery viewpoint is proposed. Two new parameters, the power delivery delay and the DeltaV time constant, are introduced to characterize the effects of the lead inductors and decoupling capacitors on the timely power delivery respectively for a high-speed PDN. The decoupling time of a PDN is accurately estimated from the power delivery delay introduced by the inductance of the discontinuities, the charge delivery speed, and the charge supply capacity of the decoupling capacitors are accurately characterized by the DeltaV time constant. Based on the two parameters, a complete and systematic power-delivery method for the design of a PDN is developed. The proposed design method is verified by SPICE, full-wave simulations, and measurements. For completion, some specific design considerations are also discussed in detail.

Efficient Method for Modeling of SSN Using Time-Domain Impedance Function and Noise Suppression Analysis

In this paper, a new method is proposed to model the simultaneous switching noise (SSN) using time-domain impedance function, which is based on the rational function in time domain. The time-domain impedance function of a power delivery network (PDN) is calculated by approximating the impedance frequency response of a PDN with a rational function, and the SSN is calculated based on switching current characteristics, which is verified by advanced design system, Hspice and measurements. Based on time-domain impedance function, the SSN suppression is also investigated, and it is found that the SSN produced by periodic switching current can be suppressed through adjusting the periods of time-domain impedance function and switching current, and a principle for random switching current is also given to prevent the occurrence of the worst case of SSN in circuit design.

An Efficient SPICE-Compatible Cavity Resonant Model for Microstrip Lines

A SPICE-compatible cavity resonant transmission line (CTL) model for a single-ended microstrip line is first presented by reducing 2-D cavity resonator to 1-D cavity resonator. This model has low efficiency since it consists of infinite higher-order components included inductors, capacitors, resistors, and ideal transformers. A modified CTL model is developed by using a fast algorithm to improve the simulation efficiency, which results in an accurate SPICE model in finite elements. Because the improved cavity resonant model uses higher-order (a little more complicated) elements in finite components, it has high efficiency in the time and frequency domain simulation. The model accuracy and simulation efficiency are validated by comparison with multiconductor transmission line and matrix rational approximation modeled methods.

Analyze and Design High-Speed Power Delivery Networks Using New Multiinput Impedances in Printed Circuit Boards

In this paper, a new input impedance, the multiinput impedance, which includes all information of the full impedance matrix, is proposed to accurately analyze and design planar power delivery networks (PDNs) in high-speed printed circuit boards and packages. The multiinput impedance includes all of the potential impacts of the other operating active power ports in both low and high frequencies. A systematical power-delivery-network analysis and design method using the multiinput impedance is developed. The global and local characteristics of the decoupled PDN are well demonstrated by the multiinput impedance, which make the analysis and design of the modern decoupled PDNs more accurate and reliable. Numerical and measured results show that the proposed multiinput impedance can characterize both the global and local characteristics of the planar PDNs with high accuracy.

Effective Radii of On-Chip Decoupling Capacitors Under Noise Constraint

As the clock frequency of a chip increases, the on-chip decoupling capacitor must be placed closer to the load to be effective. A method of efficiently defining the location of capacitor placement to meet specified noise limits is presented. Based on a single RL line model for the power distribution system, charging radius of the decoupling capacitor is calculated under the constraint of the target noise but not the constraint of being fully charged. Under the constraints of the length of the charging path and the target noise, discharging radius of the decoupling capacitor is figured out. The conversion coefficient that converts the radii of a decoupling capacitor in a single RL line model into the equivalent one in a meshed model is presented based on the expression that can exactly compute the impedance between any two points on an infinite meshed network. In this paper, it is shown that the conversion coefficient is a constant when the radius of the decoupling capacitor is taken as the per unit length of the meshed model.