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32 DESIGN007 MAGAZINE I OCTOBER 2019 they've come a long way in the last decade or so. Do you think the tool companies have done a decent job keeping up with technology and leading the way? Ritchey: I would say they're good enough, but that isn't really the problem. If you give a chainsaw to a two-year-old, you'll wind up with a ruined house, and that's the problem I face every day. I have a client in Boston with somebody who does simulations and has no idea what hardware looks like; they don't even get the models right, and then they make bad design choices, which is the problem. We need people who understand how to run things. Nolan Johnson: We're talking about all of the changes that have happened in the last 40 years, and the rate of change that you've out- lined so far. Do you see that same pace con- tinuing? Ritchey: I used to think I knew where the lim- it was, and so did lots of other people. But the only thing I can say is if there's enough money in it, someone's going to figure it out. When we reached gigabits per second, we thought we were at the end of the line, and when we reached a rise time of 20 picoseconds, we thought we were at the end of the line. But we have gone right past both. For example, I heard about a new way to make transistors so that they switch in less than a picosecond. I'm not sure on the data rate exactly, but it's going to allow about 100 gigabits per second on a sin- gle pair of wires. And that 400 Gbps that I talk- ed about earlier? That's actually eight 50 Gb/S lanes. Next, you're probably going to see four 100 Gb/S lanes. I don't know where the end is. Shaughnessy: We keep hearing that copper is not going to work beyond a certain speed. Ritchey: I heard that 30 years ago. And GE said that the epoxy-based systems, which is what FR-4-like materials are, were not going to make it. The current product I have is all 28 gigabits, and it's not even running on a low-loss laminate. It's the kind of stuff the in - dustry calls FR-4. And we have 56 ready to go, already on copper. I don't have my fin- gers on a product like that, but my clients do. So, 56 is in copper right now. When anybody talks about radio frequency (RF) and micro- wave being tough, the clock rate of a 56-giga- bit data link is 28 gigahertz; we might call that microwave, which means that the difference between RF and digital is gone. Johnson: That starts to change the landscape when you have to deal with digital logic that isn't digital because it's switching faster than it can stabilize across the chip or board. You're talking about, to some degree, a return to analog. Ritchey: Well, not to some degree. In my two- day class, the first line said, "It's all analog; it has always been analog." We were able to pre- tend it wasn't when things were slow. When things are slow, people could be lazy and not think about that. Johnson: That changes the landscape for PCB designers as they get into these technologies. Virtually everybody has to be an analog de- signer, and that's not usually how basic engi- neering is taught. Ritchey: That threshold was passed 15 years ago. The people who are struggling are the ones who don't realize that nor learn the skills. My industry is like any other industry in that most people who don't do that die out. I can't speak to all universities, but I work with the dean of engineering at my university, and I make sure that all the engineers leave know- ing that every connection they work with is a transmission line. If you give a chainsaw to a two-year-old, you'll wind up with a ruined house, and that's the problem I face every day.

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