EDN: I had interviewed a bunch of people about the early days of early IC technology when I wrote my first feature article for EDN... and the new engineers nowadays have great tools like simulation, etc., but what I see in my travels is that engineers are losing that feel and insight for the transistor and what it is doing inside that IC. So many designers just plop down an RF amplifier or data converter without a full understanding of the functionality and what’s happening inside that IC. Simulations are excellent in today’s electronics world, but I find that many designers do not know the true limitations of that tool. What do you think about that with regards to IC design and also circuit design? First let’s look at IC designers as a case.
Dobkin: For a lot of analog functions, the simulation is only so good. You still have to understand what you’re doing when you make an IC. Simulation is much better than it used to be, but there are still some things that don’t simulate, like the interaction of thermal effects in power devices. You have to know what you’re doing there. When you’re doing really high speed circuits, you need to understand what’s going on because, not only are you simulating transistor circuits, but you’re simulating the package and everything outside to make it actually work properly.
From the customer’s point of view, many of them know more about IC simulation than transistor circuit simulation. Some do, of course, but not to the depths that you need to design an IC. Plus, if you’re designing an IC, you’re using lots of MOS devices, as well as Bipolar. The small signal MOS devices are not readily available as discrete devices. We, as designers, have to know the transistors because that’s our business. We have to know how to simulate them and when the simulation doesn’t work, we have our own SPICE internally that’s used, as well as commercial simulators. And we also give our LTspice out free to our customers so they can simulate our models when they’re doing a system design. We probably have the world’s most popular SPICE with over half a million downloads.
Swanson: That’s an interesting point that Steve brought up. What I learned in the early days is that the analog guys really had to understand the silicon, more so than the digital guys did. When we talk about the digital guys, sit them down at the computer and they can immediately design things. And I understand, over the years, how we’ve had to advance our tools because the products got so complex that engineers said, ‘I can’t do this anymore without these tools.’ And I knew the tools were imperfect, but the question you asked was, ‘As we deal more and more with better simulation and better tools, are the engineers losing that feel for the silicon that they had to have 15 years ago?’
Dobkin: No (emphatically stated)—they’re not losing it. Circuits are more complicated and they still have to understand the silicon and how it interacts with the transistor next to it. The only thing that we’ve done is that we made it easier to get it right the first time. And there are still things that the simulator doesn’t handle. So we do the simulation and we do it to the best of our ability and then we do the rest of the debugging on the chip because if the simulators were perfect, everything would work the first time. And that happens a very low percentage of the time.
Editor’s note: During this interview with these two industry icons, I sensed that they know their place in the industry and in their company and effectively used the talent of their employees in a way that I personally have never seen in my 42 years in electronics. They are strong, talented, and intelligent leaders, but with a touch of humility and compassion for their employees from which other companies can learn a great deal. There is a really good book written by two Japanese gentlemen (One of them a Nikkei Electronics editor) which says a great deal about the corporate culture at Linear entitled, “The Company That No One Leaves.” This book gives wonderful insight into one of the key reasons this company has had such success over the last 34 years.
I sincerely wish Bob Swanson and Bob Dobkin many more years of success. I know that someday they will want to retire, but their influence on Linear Technology’s corporate culture will carry on to ensure the continued success of their company in the future.