-
-
News
News Highlights
- Books
Featured Books
- design007 Magazine
Latest Issues
Current IssueRigid-flex: Designing in 3D
In this month’s issue, our expert contributors share their best tips, tricks and techniques for designing rigid-flex circuits. If you’re a rigid board designer considering moving into the 3D world of rigid-flex, this issue is just what the doctor ordered!
Simulation, Analysis, and AI
Getting today’s designs “right the first time” is critical, especially with costly advanced PCBs. Simulation and analysis software tools can help you in the fight to eliminate respins. They’re not magical, but they can predict the future of your design.
Advanced, Complex & Emerging Designs
This month, our contributors focus on designing PCBs with advanced, complex and emerging technologies. We investigate design strategies for boards that are on the cutting edge of technology, or crazily complex, or so new that designers are still writing the rules as they go.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - design007 Magazine
Electronics vs. Physics: Why Vias Don’t Get Hot
December 6, 2022 | Douglas Brooks, Consultant, and Johannes Adam, ADAM ResearchEstimated reading time: 1 minute

Most of are aware that when we pass an electrical current through a trace (conductor), the trace will heat up. This temperature increase is caused by the I2R power loss dissipated in the resistance of the trace. The resistance of a copper trace is mostly determined by its geometry (cross-sectional area), and there are lots of studies trying to look at the relationship between the current down a trace (of known size) and the resulting temperature of the trace.
But the situation is much more complicated than this. There are physical properties that exist that result in helping to cool the trace. These properties are usually a combination of conduction of the heat away from the trace through the material, convection of the heat away from the trace through the air, and radiation of the heat away from the trace. A stable temperature is reached when the I2R heating equals the cooling—i.e., when the electronic and physical properties are balanced.
We have spent several (enjoyable) years collaborating on these effects. Douglas is an electrical engineer and understands electronics. Johannes is a thermodynamics physicist, and understands heat transfer. Between us we learned a lot about the thermal characteristics of vias.
Vias Don’t Get Very Hot
Traces heat because of the current through their resistance, resulting in I2R power losses. This temperature increase is caused by what we call “Joule heating”:
Joule heating is the physical effect by which the pass(age) of current through an electrical conductor produces thermal energy. This thermal energy is then evidenced through a rise in the conductor material temperature, thus the term “heating.” One can see Joule heating as a transformation between “electrical energy” and “thermal energy,” following the energy conservation principle.
We are all aware that, in general, for a given trace an increase in current through the trace will correspond to an increase in temperature of the trace. When it comes to vias, the industry guidelines have generally been to size the cross-sectional area of a via to equal that of its parent trace. Then the via will be the same temperature as the trace.
To read this entire article, which appeared in the November 2022 issue of Design007 Magazine, click here.
Suggested Items
The Drive Toward UHDI and Substrates
09/20/2023 | I-Connect007 Editorial TeamPanasonic’s Darren Hitchcock spoke with the I-Connect007 Editorial Team on the complexities of moving toward ultra HDI manufacturing. As we learn in this conversation, the number of shifting constraints relative to traditional PCB fabrication is quite large and can sometimes conflict with each other.
MKS’ Atotech to Participate in IPCA Expo 2023
09/14/2023 | MKS’ AtotechMKS’ Atotech, a leading surface finishing brand of MKS Instruments, will participate in the upcoming IPCA Expo at Bangalore International Exhibition Centre (BIEC) and showcase its latest PCB manufacturing solutions from September 13 – 15.
Designer’s Notebook: DFM Principles for Flexible Circuits
09/14/2023 | Vern Solberg -- Column: Designer's NotebookFlexible circuit applications can be as basic as furnishing electrical interconnect between two conventional circuit board assemblies, or to prove a platform for placing and interconnecting electronic components. During the planning and pre-design phase of the flexible circuit, there will be several material and process related questions that need to be addressed. Most flexible circuit fabricators welcome the opportunity to discuss their customers’ flexible circuit objectives prior to beginning the actual design process.
Elementary, Mr. Watson: Flex Designs—The Future and Beyond
09/14/2023 | John Watson -- Column: Elementary, Mr. WatsonElectronics are continually evolving, driven by innovations in printed circuit board technology. Flexible PCBs have emerged as a revolutionary force, reshaping the PCB industry and influencing the design and functionality of countless electronic devices. Some believe that flexible PCBs are a relatively newer technology, but as we will see, that is not true. Since I’m an instructor, here’s a short history lesson on how we got here and what we can expect.
IDTechEx Asks Where Flexible Hybrid Electronics Add the Most Value
09/11/2023 | PRNewswireCan digital and/or high throughput manufacturing be applied to circuit boards? Can stretchable electronics be produced without sacrificing processing capabilities?