Introduction high speed pcb design referes to the techniques that must be followed in order for a circuit to function properly when the edge rate of the signal is high. Solving signal integrity problems via rules of thumb, analytic approximation, numerical simulation, and measurement understanding how interconnect physical design impacts signal integrity managing differential pairs and losses harnessing the full power of sparameters in highspeed. Tu01 performing signal integrity analyses version v1. At lower frequencies the signals remain within data characterization and the system performs as designed.
Signal and power integrity simplified 2nd edition pdf. View a repetitive signal as it is changed using basic stamp code or by varying sensor inputs. It is the intention of this white paper to provide an overview of all the matters that affect high speed designs. The 1 practical guide to signal integrity design now updated with extensive new coverage this book brings. Confidence in measurement results repeatability from one test system to the next. Signal integrity analysis tongtong yu zhiyuan shen. This book brings together uptotheminute techniques for finding, fixing, and avoiding signal integrity problems in your design. Timing analysis and simulation for signal integrity engineers. Understanding digital signal processing, second edition is quite simply. The goal of signal integrity analysis is to ensure reliable highspeed data transmission. Accurate signal integrity analysis results product demo. Signal integrity analysis and simulation tools include ibis models by john olah and sanjeev gupta, agilent eesof eda, and carlos chavezdagostino, altera corporation s ignal integrity is a major concern for engineers working on high data rate designs. Basic principles of signal integrity december 2007, ver. 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.
Measure waveform frequency and amplitude for single and dual sine waves. Transmission line effect interconnection effect different from traditional circuit analysis. Understanding and using sparameters for pcb signal integrity. In the past 15 years, the industry has seen interconnection speeds. 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. However, the integrity of the digital quality of the signals may require very careful circuit analysis. The ability to examine highspeed signals in both time and frequency provides valuable insight into root causes of good and bad performance. A digital designers guide to verifying signal integrity primer 2. 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. Fundamentals of signal integrity analysis mentor graphics. Understanding measurement in the time and frequency. Note that the ieee emc society has a subcommittee devoted to signal and power integrity. A fully uptodate introduction to signal integrity and physical designhow design and technology selection can make or break the performance of the power distribution networkexploration of key concepts, such as plane impedance, spreading inductance, decoupling capacitors, and capacitor loop inductancepractical techniques for analyzing. Combine the driverreceiver transistor or behavioral model and signal traces.
But the overlap in design techniques at the board level is considerable. The source of a signal integrity problem is the digital output driver. Over short distances and at low bit rates, a simple conductor can transmit. A guide to making rf measurements for signal integrity. Hyperlynx signal integrity delivers advanced tools for optimizing serdes design projects.
The intricacies of signal integrity in highspeed communications introduction as communication rates continue to increase, data is being moved within systems at ever higher speeds, which leads to issues with how engineers design equipment and printed circuit boards pcbs. A signal integrity analysis program that simultaneously performs the electromagnetic field simulation and the circuit. Signal integrity and interconnect design how the electrical properties of the interconnects screw up the beautiful, pristine signals from the chips eric bogatin 2000 slide 4. This is achieved via the model assignments dialog or by manually setting the correct entry for the type field in the signal integrity model dialog, when editing the signal integrity model associated to the component placed on the schematic source document. In signal integrity, we are trying to match the impedance of a trace to a certain value, often 50 to achieve good power integrity, we want the pdn to have the lowest impedance possible. Master the usage of sparameters in signal integrity applications and gain full understanding of your simulation and measurement environment with this rigorous and practical guide. In this case, these two effects combine in different ways at the near end of the quiet line and at. Fundamentals of signal integrity powerful and complete portfolio to overcome signal degradation challenges name title. 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. Also note that the ringing may reach the hi logic level threshold, causing data errors.
Understanding digital signal processing 3rd edition. Signal integrity analysis using statistical methods. Combining equations 26 and 29 yields the relation d. If two wires are placed adjacent to each other, it is possible that the two magnetic fields interact causing a crosscoupling of energy between signals known as crosstalk. Introduction to pcad signal integrity pcad signal integrity users guide 3 supporting the ibis 3 industry standard subset for io buffer modeling. Signal integrity and power integrity in highspeed design edn. Each component will be assigned a status as described in the following table. Integrated macromodeleditor allows easy and fast definition of own models using databook or measurement values. We consider signal integrity to be emi at the circuit board level.
Digital signals integrity tutorial sonnet microstrip models. Chapter 20 signal integrity oregon state university. Modify the behavior of the interconnect to meet the constraints. Signal integrity basics intel data center solutions, iot. A signal as it emerges from the driver chip left is distorted by multiple reflections from impedance discontinuities at both ends right.
Ringing and overshoot large overshoot damage device crossing logic threshold. Find and fix weaknesses in ddr234 and lpddr234 designs with just a few clicks using the ddrx wizard. Ease of use let engineers focus on analyzing their designs rather than learning how to use test equipment. New to signal integrity analysis, or just need to brush up on the fundamentals.
Preface printed circuitboard and icpackage design used to be a field that involved expertise in layout, cad, logic design, heat transfer, mechanical engineering, and reliability analysis. A digital designers guide to verifying signal integrity primer. Signal integrity characterization techniques addresses the gap between traditional digital and microwave measurement technologies while focusing on a practical and intuitive understanding of. Effective signal integrity analysis using ibis models. The paper begins by identifying and analyzing critical nets in the design that may need signal integrity analysis. Come back to the signal integrity academy and log in to then access all the lessons. Next, it discusses transmission lines and the problems that arise from the highfrequency noise generated by rapid edgerate signals.
Whats the difference between signal integrity and power. Signal integrity principles the key to efficient highspeed product design is to take advantage of analysis tools that enable accurate performance prediction. Digital signals integrity tutorial sonnet software. It will highlight some of the common pitfalls made in ibis model generation and provide detailed solutions to.
Pdf a new approach to signal integrity analysis of highspeed. Advanced signal integrity for highspeed digital designs. Solve specific signal integrity problems including calculation of the sparameters of a network, linear simulation of circuits, deembedding, and virtual probing. Hyperlynx business and technical value technology overview. This is mostly a matter of convenience and ease of use. At lower frequencies the signals remain within data characterization and the. Configure an oscilloscope to trigger and capture a signal. Signal integrity engineering is the task of analyzing and mitigating these impairments. Understanding signal integrity signal integrity is becoming a more significant problem as clock frequencies increase. Chapter 20 signal integrity college of engineering. The design guidelines today for highspeed digital signal integrity require, as standard. Understanding models, components and libraries altium.
Understand the differences between synchronous and asynchronous serial signals. Effects such as crosstalk, coupling and delays in transmission lines have a big impact on. 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 basics by anritsu field application engineers table of contents 1. Introduction high speed pcb design referes to the techniques that must be followed in order for a circuit to function properly when. While the software offers flexibility and control over specific modellibrary locations, it does require the correct file extension to be used for each model type. Signal integrity addresses the degradation of signal quality to the point where erroneous results occur. And also, when it gets there, is it in good condition.
Review of signal integrity concepts at frequencies in the gigahertz range, a host of variables can affect signal integrity. A high speed digital output driver can only drive a few inches before the noise and delay due to the wiring become a problem. Essential principles of signal integrity is the introductory class that reveals the underlying truth of how interconnects affect signal integrity. These can include simple parallel termination on stratix gx devices as shown in figure 2, and can range to more complex resistor capacitor rc termination, in which an rc network provides a lowpass filter to remove low frequency effects, but passes the highfrequency signal. However, digital signals are fundamentally analog in nature, and all signals are subject to effects such as noise, distortion, and loss. Without the appropriate attention for signal integrity, the functioning and reliability of the board cannot be guaranteed. The presentation is intended for an audience that has little or no formal training in electromagnetic theory and microwave engineering. Topics that will be addressed include lumped discontinuities. Cisco systems, inc uses ibis models in both prelayout and postlayout analysis of highspeed networking products. Signal integrity analysis and simulation tools include ibis. Does the signal reach its destination when it is supposed to.
Understanding how interconnect physical design impacts signal integrity. The presentation is intended for an audience that has little. Identify signal integrity constraints driver to load delays including effects of crosstalk and ringback overshoot voltages other signal quality measures eye opening 2. A number of different termination methods are used to overcome this problem, depending on the application. The feature was developed to provide a way of referencing available simulation and signal integrity models. Use the search path feature to locate simulation and signal integrity models. Introduction to signal integrity what is signal integrity the importance of. Signal integrity analysis and simulation tools include.
For a more complete understanding of transmission line based circuits, an electromagnetic em model is required. The intricacies of signal integrity in highspeed communications. In digital electronics, a stream of binary values is represented by a voltage or current waveform. Myths the confusing mix of signal integrity problems lossy lines crosstalk parasitics emiemc ground bounce inductance emissions transmission lines. 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. With modern digital electronic systems pushing beyond the 1ghz barrier, packaging and board designers must now balance signal integrity and electrical performance with these other concerns. This book brings together uptotheminute techniques for finding, fixing, and avoiding signal integrity problems in. This paper will go over the evolution of ibis to its present form.
370 1625 804 1009 1359 1664 221 1604 1492 962 907 619 260 672 1259 417 1315 1392 423 959 187 653 63 1523 794 909 857 134 1038 723 319 1417 793 1224