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Thermal management expert Johannes Adam, PhD, was kind enough to take the train from his home in Leimen, Germany to meet with me during productronica in Munich. He is the creator of TRM (Thermal Risk Management) software and contributor, with Douglas G. Brooks, of PCB Trace and Via Currents and Temperatures: The Complete Analysis, 2nd Edition. He’s also working on his own book on thermal management. Johannes sat down for an interview, and I asked him to share his views on the current state of thermal management for PCBs, and what the industry can do to put the spotlight on what’s hot in PCBs.
Andy Shaughnessy: Johannes, why don't you give us a brief background of your career and how you got into thermal management?
Dr. Johannes Adam: I started in 1989 when I entered my first position in the industry. That position dealt with electronics cooling and the simulation of air flow in telecom racks of that time. The company that employed me was looking for a physicist who was able to do programming and to do user support. That was perfect for me, although I'm a professional astrophysicist.
Shaughnessy: There are not many astrophysicists in the PCB world.
Adam: A few. I never did serious observations with a telescope; instead I did programming solving differential equations in astrophysical scenarios. But, of course, there are intersections between both. We talk about the physics of heat flow and heat transfer in PCBs, and all this can be formulated in differential equations, which of course theoretical physicists are educated to solve.
Shaughnessy: What came next for you?
Adam: After seven years I joined another company, Flomerics. They were doing this business more professionally: solving airflow and heat transfer inside enclosures, cooling by heat sinks, cooling by fans, etc., all done numerically on the computer. I was doing some basic analysis of PCBs. In 2009, I decided to build up my own business and to concentrate on the heat flow and temperature in PCBs. For more than a decade I presented a seminar on thermal issues in PCBs for electrical engineers and PCB designers. From those, and from customers, I learned what data they have and what they would need in order to calculate PCB temperatures before the manufacturing or the lab process. In my eyes, designing printed boards is an art and manufacturing is amazing.
All of this experience, previous and new, then went into my new TRM software. The basic idea is that you have an existing design, whether finished or just in the experimental state. You import the Gerber files from the layout software, add components, the dissipated power, and optionally assign Ampere values to traces, and then simulate what temperature can be expected under certain ambient conditions.
Shaughnessy: So, you think there is kind of a disconnect? Perhaps the EEs don’t realize that they don't have all the data?
Adam: Yes, and some don't even know the proper data. I guess that university education is rare as far as this subject is concerned. Typically, thermal resistance is all about thermal management. But thermal resistance depends on anything and everything. It depends on the boundary conditions, on the layer count, on the vicinity of a component or the trace you are interested in.
To read the rest of this article, which appeared in the December 2017 issue of The PCB Design Magazine, click here.