In my previous blog, I talked about how a printed circuit board is nothing more than a path for signals and power to travel to and from ICs. For a long time, the path was “short” enough to not even matter. Then signals became fast enough that the board became a signficant part of the circuit, and the realm of analysis known as “signal intgrity” was born. Really, signal integrity is just the analysis of analog characteristics of digital busses. Which is a little funny, since many “analog” simulations will ignore the board characteristics (although that trend is changing, as speeds of “analog” busses are ever-increasing).
But the other aspect of design spawning the need for new analysis is the size of the ICs. There are so many power-hungry transistors on the ICs nowadays that you need to analyze the power feeding them as well. Just getting the appriopriate DC voltage to these ICs is a challenge, as I discussed last week. But the AC aspect is also a challenge; decoupling analysis can be pretty tricky. However, the consequence for ignoring these problems is design failure.
I talk more about the unique aspects of these different kinds of analysis, and compare and contrast them, in my recent article in Electronic Design magazine:
Take a peek…