Timing analysis and simulation for signal integrity engineers. In modern highspeed digital designs, power distribution networks pdns using power and ground planes are commonly used where decoupling capacitors are necessary to provide charge for logic transitions and, at the same time, to mitigate the noise generated during device switching. My question is, why am i seeing so much excessive ringing when the signal has a risefall time of 4ns and the length of the trace is less than 1. Signal integrity engineering is the task of analyzing and mitigating these impairments. Fundamentals of signal integrity powerful and complete portfolio to overcome signal degradation challenges name title.
A foundation for signal integrity introduction signal integrity is a growing priority as digital system designers pursue everhigher clock and data rates in computer, communications, video and network systems. Two significant issues that should be considered are false switching and double. Signal integrity is in your future there are two kinds of designers, those with signalintegrity problems and those that will have them. Eric bogatin, cto, gigatest labs signal integrity engineering and training 4 s. Signal integrity problems, including delays, ringing, crosstalk, and emi, can be identified through careful use of simulation. Signal integrity analysis tongtong yu zhiyuan shen. The fpga designer must know and understand important signal integrity issues that have become a critical part of fpga design. Another method of improving signal integrity is to ensure that all chips are adequately decoupled.
Does that suggestion mean ringing and overshoot cannot occur if the signal rise time exceeds the roundtrip time even though an. These include partial inductance as distinct from loop inductance, the origin of ground bounce and emi, impedance, transmission line discontinuities, differential impedance, and attenuation in lossy lines affecting the collapse of. Signal integrity basics intel data center solutions, iot. Mathcad modelling scripts includes appendix c coded for mathcad v. Ringing and overshoot large overshoot damage device crossing logic threshold. Signal integrity applied electromagnetics and professional. Modify the behavior of the interconnect to meet the constraints.
Emc and signal integrity in highspeed electronics li er. For engineers wading into the waters of higher data rates and pam4, this special issue of signal integrity journal on pam4ber and related topics, sponsored by anritsu, brings some of the most recent pieces on these topics into one collection. Signal integrity and power integrity issues at system. For descriptions of the other manuals in the hspice documentation set, see the next section, the hspice. Begin to see that quality or integrity of textbook signals different from we see in out circuits signal edges and transitions not as crisp see oscillations called ringing as signals change state signal propagation meander to destination. Most books either present a lot of mathematical derivation or present formulas as facts, merely describing what they are. Drawing on his work teaching several thousand engineers and graduate students, worldrenowned expert eric bogatin systematically presents the root causes of all six families of signal integrity, power integrity, and. Signal integrity and power integrity issues at system level. Signal integrity considerations with mpc5500based systems, rev. Signal integrity engineering is at all levels of electronics packaging, from internal connections of an ic through the package, the printed circuit board pcb, the. Master index to highspeed digital engineering publications by dr. We hear about a lot of signalintegrity noise problems, such as ringing.
Board layout issues improper termination circuit problems. Emphasis is placed on real problems that the author has encountered in his professional career, integrating problemsolving strategies and real signalintegrity case studies throughout the presentation. Hardware and layout design considerations for ddr memory interfaces, rev. Many signal integrity problems are electromagnetic phenomena in nature and hence related to the emiemc discussions in the previous sections of this book. At todays high operating frequencies, anything that affects a signal s rise time. Lathi, crc press other books signals and systems, richard baraniuks lecture notes, available on line digital signal processing 4th edition hardcover, john g. Signal integrity considerations with mpc5500based systems. Appendix c includes all the equations from the back of the book, with examples. Drawing on his work teaching several thousand engineers and graduate. Integrated macromodeleditor allows easy and fast definition of own models using databook or measurement values. The key differentiator between our book and all the others written on signal integrity, is the starting level for the material. If you are looking to learn about signal integrity it will be much easier to get there from a background in engineering or physics than from a background in cad. It builds a solid understanding of ringing, crosstalk, ground bounce, and power supply noise as they exist on printed circuit boards.
A digital designers guide to verifying signal integrity primer 2. Inside this manual this manual contains the chapters described below. When the speed of the signal increases, a designer must be aware of the high speed issues of ringing, power supply noise, crosstalk, electromagnetic inteference. Unlike other books that take a general approach to signal integrity, this book takes a few deep dives to apply the simple principles to explain relatively complex effects. Any product designer that touches the product can have an impact on signal integrity. Digital designs have not traditionally suffered by issues associated with transmission line effects. Most books suggest that overshoot and ringing arise if the signal rise time is less than the roundtrip delay of the transmission line. Identify signal integrity constraints driver to load delays including effects of crosstalk and ringback overshoot voltages other signal quality measures eye opening 2. This book describes in the simplest possible terms, the signal integrity problems and the. For example, most signalintegritysoftware packages calculate the impedance and loss of transmission lines using a 2d, quasistatic, discrete field solver. The flexible frequency modulation of programmable clocks also simplifies.
Students are challenged to think about managing complex design projects and implementing successful engineering and manufacturing processes. However, with increasing signal speeds, you get higher frequencies, which can affect both the analog and digital properties of the system. Introduction to pcad signal integrity pcad signal integrity users guide 3 supporting the ibis 3 industry standard subset for io buffer modeling. The goal of signal integrity analysis is to ensure reliable highspeed data transmission.
Good signal integrity practices will limit the amount of crosstalk, ground bounce, and ringing by controlling and implementing proper noise margins, impedance matching, and decoupling. Topics that will be addressed include lumped discontinuities. Signal and power integrity simplified download free pdf. Systemlevel simulation of highspeed systems with effect of external environment is described.
The resulting spectrum will have peaks at the ringing frequency. As an example, consider a driver chip that is sending a signal out on a very short interconnect, a controlledimpedance line on a circuit board to a receiver figure 1. Vlsi era, digital chip circuit design and layout were manual processes. Emi from a component or the system eric bogatin 2000 slide 6. Maintaining signal integrity means preventing the electrical properties of interconnects from disrupting this undistorted state. Advanced electromagnetics and electronic systems lab. High q factor resonances ring forever in the time domain. However, as speed increases, highfrequency effects take over and even the shortest lines can suffer from problems such as ringing, crosstalk, reflections, and ground bounce, seriously hampering the integrity response of the signal. A digital designers guide to verifying signal integrity. Section 6 noise, crosstalk, jitter, skew, and emi backplane designers guide this section discusses backplane signal integrity, focusing on the phenomena and effects that can disrupt clean signals and high signal integrity. A digital designers guide to verifying signal integrity primer.
Reducing emi and improving signal integrity using spread. Understanding signal integrity signal integrity is becoming a more significant problem as clock frequencies increase. The highspeed digital design collection includes professionallyrecorded versions of all three of his highspeed digital design seminars, the same seminars he taught for 20 years at oxford university and other sites worldwide, plus his archive of over 400 technical articles. Essential principles of signal integrity is the introductory class that reveals the underlying truth of how interconnects affect signal integrity. And also, when it gets there, is it in good condition.
The book signal integrity for pcb designers helps you understand the effects of the layout and interconnect on the integrity of the signal. Highspeed digital design overview signal integrity. Identify signal integrity problems with integrated measurement tools. This book brings together uptotheminute techniques for finding, fixing, and avoiding signal integrity problems in selection from signal and power integrity simplified, third edition book. Good signal integrity practices will limit the amount of crosstalk, ground bounce, and ringing by controlling and implementing proper. Tu01 performing signal integrity analyses version v1.
The probe is connected directly at the pin of the oscillator. Emc and signal integrity in highspeed electronics li erping, phd, ieee fellow. Download the latest sij ebooks signal integrity journal. Connecting more than two nodes, the ringing becomes an issue. An ideal waveform top has variations due to the effects of the signal path, such as the ringing shown in the bottom waveform. Signal integrity and crosstalk emc and the printed.
Hardware and layout design considerations for ddr memory. Some of the main issues of concern for signal integrity are ringing, crosstalk. This book brings together uptotheminute techniques for finding, fixing, and avoiding signal integrity problems in your design. Emphasis is placed on real problems that the author has encountered in his professional career, integrating problemsolving strategies and real signal integrity case studies throughout the presentation. Fundamentals of signal integrity mouser electronics. Rail collapse in the power and ground distribution network 4. What causes ringing on a pcb and how to solve it altium. This means, it is necessary to suppress the ringing. Enemies of signal integrity include noise, crosstalk, jitter, skew, and electromagnetic interference emi. Signal integrity is especially critical for highspeed design.
To ensure the signal integrity, it is also necessary to ensure the lines are well matched so that ringing is prevented. Once potential problems have been identified, layout can be constrained to improve performance, and termination strategies. Understanding the importance of signal integrity ieee. Signal integrity basics by anritsu field application engineers table of contents 1. Mar 12, 2020 the articles and columns contained in this section come from members of the signal integrity journals editorial advisory board eab. Signal integrity issues and printed circuit boards. The field solver depends on six crucial assumptions. Calculating trace lengths electrically long traces loading due to discontinuities. At low frequencies, you should not experience any major problems with signal integrity. With unterminated stublines the ringing becomes serious.
Pci express signal integrity and emi july 2, 20 3 revision 1. Howard johnson, containing publications first printed in ed and edn magazines, private newsletters, and. Signal quality is maintained from a driver to a receiver interference between two or more signals doesnt degrade the signal the signals dont damage any devices power distribution network pdn integrity is maintained timing margins are achieved 06052007 hasnain syed 2. This can add additional spikes that may be transmitted around the circuitry.
In star topologies and hybrid topologies, the ringing can corrupt the communication. In this issue, you will find a very interesting paper on power integrity. Loss of signal integrity with pcb units has long been an ongoing concern, so its important to keep signal integrity pcb layout considerations in mind when manufacturing, selling or purchasing printed circuit boards. A square wave clock signal concentrate its power in narrow frequency harmonics. For todays highspeed boards and ics, signal integrity performance is as important to specify as digital functionality or clock speed. The oscillation is a response to a sudden change in the input signal, like turning it. The presentation is intended for an audience that has little or no formal training in electromagnetic theory and microwave engineering. Designing a robust and cost effective product is not about blindly following a general set of design rules, rather it is about following a process that helps you apply your engineering intuition to. The presentation is intended for an audience that has little. Signal and power integrity simplified 2nd edition hardcover eric bogatin author isbn10. Signal and power integrity simplified, third edition book. However, as speed increases, highfrequency effects take over, and even the shortest lines can suffer from problems such as ringing, crosstalk, reflections and ground bounce, seriously hampering the response of the signalthus damaging signal integrity.
Chapter 20 signal integrity oregon state university. Pdf signal and power integrity simplified download ebook. Does the signal reach its destination when it is supposed to. The oscillation is a response to a sudden change in the input signal, like turning it on or switching. A signal with ringing left is returned to an acceptable state by the addition of a series termination resistor on the driver side right. Review of signal integrity concepts at frequencies in the gigahertz range, a host of variables can affect signal integrity. In the realm of highspeed digital design, signal integrity has become a critical issue, and is posing increasing challenges to the design engineers. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have. Also note that the ringing may reach the hi logic level threshold, causing data errors. I soldered a small wire onto the ground pad and i connect the ground clip there. Copies of this presentation are available on the signal integrity academy web site. Deek offers a simple method to reverse engineer the output impedance of any drivermeasure its open circuit voltage and find the load resistance when the output voltage. You may experience reflections, ground bounce, crosstalk and ringing at higher frequencies, which can seriously damage the integrity of your signal.
In the recently released book larry smith and i wrote, principles of power integrity simplified, we offered a spreadsheet to go along with the book, especially the last chapter. At lower frequencies the signals remain within data. Fundamentals of signal integrity powerful and complete portfolio to overcome signal degradation challenges. Unfortunately, it doesnt always provide the right answers. In this column area, the eab will talk about issues related to power integrity. This further reduces radiated emi by decreasing the total highfrequency harmonic content of the signal. Astar, institute of high performance computing ihpc national university of singapore. The original book deals with a broad spectrum of highspeed phenomena. When were talking about printed circuit boards, or other electronic systems, ringing is a voltage or current output that oscillates like a ripple on a pond when its seen on an oscilloscope. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have been printed.
437 71 730 1130 887 1197 655 1191 608 1246 1268 902 670 1155 321 710 1500 692 854 807 356 259 273 655 704 634 1452 632 1211 530 848 1141 548 949 385 9 301 708 814 656 1125 37 834