Mohamed Ramdani

The Electromagnetic Compatibility of Integrated Circuits—Past, Present, and Future

Throughout the decades of continuous advances in semiconductor technology, from the discrete devices of the late 1950s to todays billon-transistor system-on-chip, there have always been concerns about the ability of components to operate safely in an increasingly disruptive electromagnetic environment. This paper provides a nonexhaustive review of the research work conducted in the field of electromagnetic compatibility (EMC) at the IC level over the past 40 years. It also brings together a collection of information and trends in IC technology, in order to build a tentative roadmap for the EMC of ICs until the year 2020, with a focus on measurement methods and modeling approaches.

A Direct Power Injection Model for Immunity Prediction in Integrated Circuits

This paper introduces a complete simulation model of a direct power injection (DPI) setup, used to measure the immunity of integrated circuits to conducted continuous-wave interference. This model encompasses the whole measurement setup itself as well as the integrated circuit under test and its environment (printed circuit board, power supply). Furthermore, power losses are theoretically computed, and the most significant ones are included in the model. Therefore, the injected power level causing a malfunction of an integrated circuit, according to a given criterion, can be identified and predicted at any frequency up to 1 GHz. In addition to that, the relationship between immunity and impedance is illustrated. Simulation results obtained from the model are compared with measurement results, and these demonstrate the validity of this approach.

EMC Assessment at Chip and PCB Level: Use of the ICEM Model for Jitter Analysis in an Integrated PLL

This paper deals with the use of the integrated circuit electromagnetic model (ICEM) to analyze, predict, and optimize autocompatibility and electromagnetic emission at chip and system level. ICEM is currently under standardization process (IEC62014-3). The basic ICEM architecture is composed of a power distribution network model and an internal current source modeling digital activity. Such an approach enables the description of any kind of digital or mixed-signal design. This model is useful either for the IC manufacturer or the system manufacturer. The power distribution network of a printed circuit board (PCB) can be optimized using this model by choosing the number and the right values of decoupling capacitors as well as the size of power planes. The IC manufacturer may check out the autocompatibility of an IC and determine the number of power pins as well as the package to be used. As an example, jitter analysis of an integrated phase-locked-loop can be performed using ICEM. This paper demonstrates that this jitter can be predicted by simulation and that corrective solutions can be provided and checked out before implementation

Assessment of the Immunity of Unshielded Multi-Core Integrated Circuits to Near-Field Injection

This paper presents a comparative assessment of the electromagnetic immunity of 4 integrated logic cores to near-field injection. These cores, located on the same die, are identical from a functional point of view, but differ by their design strategies. The injection is performed above each core according to the 6 components of the electromagnetic field, using appropriate probes. These results demonstrate that the die and bondwires of an integrated circuit can be sensitive to both magnetic and electric fields, and that some design rules can improve the immunity of integrated circuits to near-field interference.

Simple, Taylor-Based Worst-Case Model for Field-to-Line Coupling

To obtain Electromagnetic Compatibility (EMC), we would like to study the worst-case electromagnetic field-induced voltages at the ends of Printed Circuit Board (PCB) traces. With increasing frequencies, modelling these traces as electrically short no longer suffices. Accurate long line models exist, but are too complicated to easily induce the worst case. Therefore, we need a simple analytical model. In this article, we predict the terminal voltages of an electrically long, two-wire transmission line with characteristic loads in vacuum, excited by a linearly polarised plane wave. The model consists of a short line model (one Taylor cell) with an intuitive correction factor for long line effects: the modified Taylor cell. We then adapt the model to the case of a PCB trace above a ground plane, illuminated by a grazing, vertically polarised wave. For this case, we prove that end-fire illumination constitutes the worst case. We derive the worst-case envelope and try to falsify it by measurement in a Gigahertz Transverse Electromagnetic (GTEM) cell.

Predicting the immunity of integrated circuits through measurement methods and simulation models

This paper introduces complete simulation models of typical electromagnetic immunity tests for integrated circuits (ICs). Direct Power Injection (DPI), Near-field (NF) and Very- Fast Transmission Line Pulsing (VF-TLP) experiments are modeled accurately, and comparisons between simulations and measurements for each set-up demonstrate the validity of this approach and lead to the development of an immunity prediction method for ICs.

Fundamentals and Theory

This chapter presents five sections explaining some EMC fundamentals and theoretical tools, which aim at providing the reader with basic, understandable and useful theory in the EMC field. The first section deals with the basic theory of electromagnetic emission (electrical dipole, magnetic loop, near field and far field approximations), the second section then brings the concept of the Fourier transform and useful units in frequency domain. The third section deals with transmission lines theory, while the fourth section handles the modeling of RLC passive elements and interconnect in high frequency, the fifth section deals with S-parameter definitions.

ICEM model extraction: a case study

A new model called ICEM (integrated circuits electromagnetic model) is currently under standardization process. It is proposed under the IEC 62014-3 reference and is aimed at modeling radiated and conducted parasitic emissions of integrated circuits on printed circuit boards (PCB). This paper deals with the validation and extraction of ICEM parameters on an integrated circuit (microcontroller), allowing the designer to predict conducted noise level. First of all, this paper describes an approach for ICEM model generation on an integrated circuit. An 8-bit microcontroller (RISC, AVR Core, etc.) has been selected as the test vehicle. The test board and the measurement setup are then described. Finally, the influence of design parameters like decoupling capacitors is discussed.

Using a Modified Taylor Cell to Validate Simulation and Measurement of Field-to-Shorted-Trace Coupling

Predicting the immunity of electronic boards to radiated electromagnetic interference requires the computation of the coupling efficiency of an electromagnetic field to PCB traces. In the case of complex PCBs, full-wave electromagnetic solvers are convenient, yet at the expense of simulation time. Therefore, this paper introduces the extension of a modified Taylor-based analytical model to the case of traces terminated at one end by a noncharacteristic impedance. This model makes it possible to determine the far-field-to-trace coupling using only a sum of closed-form equations. When applied to a shorted, meandered PCB trace, it was found to be as precise as 2.2 dB average absolute error with respect to GTEM measurements, which demonstrates its relevance for immunity prediction. Moreover, the full-wave simulation of this case study was validated using the extended model and found to be as precise as 1.4 dB average absolute error.

SMPS Tools for EMI Filter Optimization

This paper deals with conducted emissions in SMPS (Switched Mode Power Supplies). It aims to optimize the size of the input EMI (Electro-Magnetic Interference) filter. A topological method worked out by G.Kron, based on multiphysical and multiscale approach, is used in time and frequency domains. A genetic algorithm is also used to optimize the physical dimensions of the filter. Thus, thanks to waveform estimations and the filter modelling, EMI filtering can be taken into account at the design stage.