Reinaldo Perez

Signal integrity issues in ASIC and FPGA design

Most often when addressing electromagnetic compatibility issues in the electronic design of analog and digital circuits, EMC principles such as grounding, coupling, emissions, shielding, etc. are commonly scrutinized. Studies and research within EMC normally extends to the more fundamental principles of interference and compatibility as developed from the basic framework of electromagnetic theory. This framework has lately been extended to include computational methods for the solution of interference problems that are otherwise difficult to address analytically. However, it is usually observed that newly designed hardware first encounter electromagnetic interference in the area of signal integrity where the design must overcome the inherited electromagnetic constraints imposed by high speed logic and the very low noise threshold levels of analog components. Addressing the most important signal integrity issues in digital electronic design, and which are common to most present design, are briefly covered in this paper, as well as the relevance of such issues to the electromagnetic compatibility principles previously mentioned.

Methods for Spacecraft Avionics Protection Against Space Radiation in the Form of Single-Event Transients

This paper presents a design philosophy for protecting spacecraft avionics from the effects of single-event transients caused by high-energetic charged particles in the space environment. The design philosophy has resulted in a proven concept over the many years of actual implementation in real avionics in real space missions. Only an overview of this design philosophy is presented. The paper first addresses the science of the space environment as it relates to high-energy charged particles. It includes the derivations of important parameters in high-energy particle physics as it applies to interactions with semiconductor electronic in component integrated circuits. The paper then transitions to explore some general methodologies widely used in the industry to control the damaging effects of single-event transients caused by the space environment. The paper then shifts emphasis to the main subject of design methods and philosophies, with examples of how spacecraft avionics can be designed and built with a certain level of immunity against the possible catastrophic effects of single-event transients. These design principles are presented briefly, but with enough detail to provide a general overview.

Steps for the proper development of an EMC Control Plan

The development of a major electronic product in a company is usually preceded by the writing of an EMC Control Plan. The EMC Control Plan is written by the senior electromagnetic compatibility engineer and eventually reviewed and approved by management. A product being developed will adhere to the EMC Control Plan. The quality of the EMC Control Plans vary, depending on who writes it, how important is EMC in the culture of the company, the importance of the product itself to the future profitability of the company, and how innovative is the product to be developed. Nevertheless, the proper writing of an EMC Control Plan is crucial to the development of a product that is well designed with EMC in mind. In this work we outlined all the aspects of a well written EMC Control Plan. A well written EMC Control Plan outlines not only testing but design, development, and manufacturing issues. It is intended that present and future EMC engineers could use this EMC Control Plan as a baseline for their companies.

Teaching electromagnetic compatibility at the graduate level

Graduate-level education is probably one of the best places to fit an advanced electromagnetic compatibility (EMC) course. To bring interest into a graduate level electromagnetic compatibility course, the material presented should incorporate novel approaches beyond the traditionally taught subjects. In this discussion, the computer age is brought into the teaching of this subject. This is accomplished by examining some of the most successful codes developed for EMC to study their different modeling techniques. Students are introduced to the physics and functionality of several electromagnetic analysis codes which can be useful in EMC analyses. A basic course in EMC would serve as a prerequisite.<<ETX>>

Correlating the EMC analysis and testing methods for space systems in MIL-STD-1541A

A study was conducted to improve the correlation between the electromagnetic compatibility (EMC) analysis models stated in MIL-STD-1541A and the suggested testing methods used for space systems. The test and analysis methods outlined in MIL-STD-1541A are described, and a comparative assessment of testing and analysis techniques as they relate to several EMC areas is presented. Suggestions on present analysis and test methods are introduced to harmonize and bring the analysis and testing tools in MII-STD-1541A into closer agreement. It is suggested that test procedures in MII-STD-1541A must be improved by providing alternatives to the present use of shielded enclosures as the primary site for such tests. In addition, the alternate use of anechoic chambers and open field test sites must be considered.<<ETX>>

Controlling EMI in telecommunications ICs

Todays complex, deep submicron system-on-chip (SOC) designs, with their smallest feature sizes, increased densities, higher frequencies, and lower supply voltages, have made noise coupling at the packaging and substrate level, key issues for wireless designers of ICs. Until recently, designers have been forced to use rule-of-thumb methodologies to guard against crosstalk at the substrate and packaging level. New substrate modeling and package modeling analysis tools outline in this work have made it possible for designers to understand the effects of noise coupling across their chips substrates and packaging, and to address the problem early in the design cycle. Finally, transient voltages are a fact of life in telecommunications equipment. The increase complexity of semiconductors has made them more sensitive to the effects of overvoltage due to decreasing geometries. In this work, the authors suggest the selection of protection circuits.

A comparative assessment between linear and switching power supplies in portable electronic devices

The choice between linear and switching power supplies at the board level is sometimes clear cut. However, as the current demands rises and operating voltages sink, considerations must be paid to such factors as power wastage, filtering needs, available board space, and economics. A comparative assessment is made between linear and switching power supplies which should guide the power supply engineer in making intelligent choices as to which option to follow. Design techniques which account for the usage of both linear and switching element in a single board design are also addressed and which may be of future interest to power supply designers.

Parallel computing in the teaching of electromagnetic computational methods for analyzing EMC problems

Parallel computational algorithms are introduced during the final part of a graduate level EMC course in which computational electromagnetic (CEM) methods are taught as useful tools for solving EMI problems. Examples on the use of CEM are discussed with the students. Students are first taught the history, theory, and methodologies used in parallel computing with mathematical examples. Then, parallel computational methods and approaches are addressed for two popular CEM techniques, the method of moments (MOM) and the finite difference time domain (FDTD) method. The paper emphasizes simple conceptual algorithms for parallelization of an FDTD code as taught to students. Parallel algorithms for MOM are also covered. Subsequent work deals with solving practical but complex EMI problems using parallel algorithms in CEM tools.

Proper design of grounding for SMPS converters

Converters that are used in a switching mode power supply (SMPS) are usually well designed internally so as to maximize efficiency and minimize output noise. However, deficiencies in the distribution of power and grounding within the PCB where the SMPS converters will be located can negate many of the advantages provided by these converters. It is shown that inductive and capacitive effects in the way SMPS converters are used in a PCB are one of the major causes of high conductive emission in PCBs. Furthermore, it is shown that changes in grounding layouts can affect these inductive and capacitive effects.

Proper design of bypass capacitance in wideband operational amplifiers

Wideband operational amplifiers are essential in all signal acquisition and signal manipulation applications. Wide bandwidth operational amplifiers can accept a wide range of analog input frequencies and provide a wide range of outputs. However, improper use of bypass capacitance can degrade the noise and stability performance of wideband amplifiers causing the correct output to be accompanied also but adjacent random outputs, or noise; which can quickly deteriorate the signal to noise ratio. A detailed study on the proper use of bypass capacitance in wideband amplifiers follows with the derivation of a series of design formulas.