BoardSurfers: High-Speed Design Signal Integrity Challenges and Solutions

Usually, people start a blog by stating something dramatic and we used to bring drama to our otherwise staid stuff on PCB design by mentioning High Speed and Signal Integrity. No more. High-speed is the norm because even if your data is not in the range of a few tens of thousands of GB, the size of your board is certainly diminishing. And Signal Integrity follows – a high-speed design must work and be reliable. And so signal integrity cannot be overlooked. In short, all of us in the electronic design industry cannot do without high-speed designs and, therefore, must at least dabble with signal integrity.

The industry, of course, realized this long back and we now have very reliable applications, rules, conventions, and methodologies to design high-speed designs and perform signal integrity analysis. Take Allegro® PCB Editor, for example, that gives you a plethora of features and functions to ease high-speed boards or the Cadence® Sigrity suite of products that gives you the state-of-art, cutting-edge analysis applications.  

The Challenge

The challenge, therefore, is not in the lack of applications or best practices or even expertise, rather the challenge is easing the life of PCB designers and ensuring reliable end products. When I say the life of PCB Designers, you all know what I mean, reducing cycles and enhancing quality. One way to do that is to deal with the electrical issues that are usually caught by SI engineers at a later design stage to an earlier phase, into the domain of the board engineers. This makes sense because many electrical issues have underlying physical factors. So, as a board designer, I want to get useful and usable information about the layout of the board that could result in electrical problems.

The Solution

And, as a board designer, I want to get that useful and usable information from the known territory – from the application that I use to design my board - and without having to learn a completely new set of tools. I will be even happier if I am guided while doing my analysis, step by step, and then if the result is shown in the most intuitive and user-friendly way. The good news is that Allegro® PCB Editor does all that and more. Yes, now, you get Sigrity technology-driven high-speed checking and analysis capability from within PCB Editor. You must have noticed Paul McLellan's recent blog post, Sigrity Aurora: In-Design Analysis, which talks about Sigrity Aurora that, in Paul's own word, "puts all the power of the Sigrity engines under the Allegro user experience." So, you can perform all of the following analyses from PCB Editor and that too without learning the Sigrity tools end-to-end:

• Impedance
• Coupling
• Crosstalk
• Reflection
• Return Path
• IR Drop

And each of these analysis environments comes with a workflow guide to reduce learning time even further.

But that’s not all. You have choices in how you want to view the result. Are you very analytical? Well, then opt for a tabular format. Or, maybe you will like plots. Or, maybe like me, you are visual and will prefer Vision overlays – results in your canvas itself as color-coded overlays on the traces and routes, similar to seeing traffic congestions in your map apps while driving.

Conclusion

In the coming months, we will be talking more about each of the analyses, and wherever possible, we will point you to specific sample designs or content that goes deeper into the technologies. We will also explain some very useful features, say, the filtering of results, along the way. So, keep an eye on this page. Although there is much more to Sigrity Aurora, as Paul's blog discusses, we will concentrate only on the five In-Design Analysis types we mentioned. Till then you might want to view these useful videos on different aspects of the analyses.