-
- News
- Books
Featured Books
- design007 Magazine
Latest Issues
Current IssueLevel Up Your Design Skills
This month, our contributors discuss the PCB design classes available at IPC APEX EXPO 2024. As they explain, these courses cover everything from the basics of design through avoiding over-constraining high-speed boards, and so much more!
Opportunities and Challenges
In this issue, our expert contributors discuss the many opportunities and challenges in the PCB design community, and what can be done to grow the numbers of PCB designers—and design instructors.
Embedded Design Techniques
Our expert contributors provide the knowledge this month that designers need to be aware of to make intelligent, educated decisions about embedded design. Many design and manufacturing hurdles can trip up designers who are new to this technology.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - design007 Magazine
Brooks' Bits: Your Traces Have Hot Spots!
August 24, 2016 | Douglas G. Brooks, PhDEstimated reading time: 1 minute
Your traces have hot spots. At least, those that carry a moderate current do. Surprised? Well, I was a little surprised, too, when I looked at this a little more closely.
One chapter in my recent book focuses on fusing current. It contains the image (Figure 1), captured on video, which shows a 20 mil wide trace that had been heated for about 15 minutes, just at the moment of fusing. There are several interesting things in this image, especially how the smoke is blown out from under the trace at certain points with considerable pressure. But note that the trace fuses at a point, not everywhere along the trace. It is clear from observation that the trace is much hotter at some points than at others.
Figure 2 appeared in a separate article published in 2010. (It has been enhanced after some collaboration with the author of that article.) The image shows a trace being heated to the melting point. At this stage, the hottest portions of the trace are over 600°C, but other areas remain in the 200°C temperature range.
The reasons for the temperature variation at high temperatures are not too hard to understand. There may be minor contamination under the trace or in the copper that accounts for it. Certainly, at higher temperatures (say above about 300°C) the board may begin to delaminate, severely disrupting its cooling characteristics. There may be small variations in trace width or thickness that help account for the delam, and these effects would be randomly distributed along the length of the trace.
But in a variety of lower-temperature studies, I personally took trace temperature measurements using a small thermocouple. I noticed that if I moved the thermocouple slightly, I would get a different temperature reading. Not by much, maybe 1.0° or 1.5°C. This is more than the resolution of the thermocouple, but not enough for me to be satisfied that the differences were real. So I began to wonder if these variations in temperature appeared at lower trace temperatures, say in the 40°C. range.
To read this entire article, which appeared in the August 2016 issue of The PCB Design Magazine, click here.
Suggested Items
Insulectro’s 'Storekeepers' Extend Their Welcome to Technology Village at IPC APEX EXPO
04/03/2024 | InsulectroInsulectro, the largest distributor of materials for use in the manufacture of PCBs and printed electronics, welcomes attendees to its TECHNOLOGY VILLAGE during this year’s IPC APEX EXPO at the Anaheim Convention Center, April 9-11, 2024.
ENNOVI Introduces a New Flexible Circuit Production Process for Low Voltage Connectivity in EV Battery Cell Contacting Systems
04/03/2024 | PRNewswireENNOVI, a mobility electrification solutions partner, introduces a more advanced and sustainable way of producing flexible circuits for low voltage signals in electric vehicle (EV) battery cell contacting systems.
Heavy Copper PCBs: Bridging the Gap Between Design and Fabrication, Part 1
04/01/2024 | Yash Sutariya, Saturn Electronics ServicesThey call me Sparky. This is due to my talent for getting shocked by a variety of voltages and because I cannot seem to keep my hands out of power control cabinets. While I do not have the time to throw the knife switch to the off position, that doesn’t stop me from sticking screwdrivers into the fuse boxes. In all honesty, I’m lucky to be alive. Fortunately, I also have a talent for building high-voltage heavy copper circuit boards. Since this is where I spend most of my time, I can guide you through some potential design for manufacturability (DFM) hazards you may encounter with heavy copper design.
Trouble in Your Tank: Supporting IC Substrates and Advanced Packaging, Part 5
03/19/2024 | Michael Carano -- Column: Trouble in Your TankDirect metallization systems based on conductive graphite or carbon dispersion are quickly gaining acceptance worldwide. Indeed, the environmental and productivity gains one can achieve with these processes are outstanding. In today’s highly competitive and litigious environment, direct metallization reduces costs associated with compliance, waste treatment, and legal issues related to chemical exposure. What makes these processes leaders in the direct metallization space?
AT&S Shines with Purest Copper on World Recycling Day
03/18/2024 | AT&SThe Styrian microelectronics specialist AT&S is taking World Recycling Day as an opportunity to review the progress that has been made in recent months at its sites around the world in terms of the efficient use of resources: