-
- News
- Books
Featured Books
- smt007 Magazine
Latest Issues
Current IssueComing to Terms With AI
In this issue, we examine the profound effect artificial intelligence and machine learning are having on manufacturing and business processes. We follow technology, innovation, and money as automation becomes the new key indicator of growth in our industry.
Box Build
One trend is to add box build and final assembly to your product offering. In this issue, we explore the opportunities and risks of adding system assembly to your service portfolio.
IPC APEX EXPO 2024 Pre-show
This month’s issue devotes its pages to a comprehensive preview of the IPC APEX EXPO 2024 event. Whether your role is technical or business, if you're new-to-the-industry or seasoned veteran, you'll find value throughout this program.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - smt007 Magazine
Stop Relating Trace Temperature to Current Density
October 1, 2020 | Douglas G. Brooks, PhDEstimated reading time: 1 minute
Many design engineers and even many software suppliers make the significant mistake of equating changes in trace or via temperature with current density. This is incorrect at best and dangerous at worst. There is little if any correlation between temperature and current density. Current and trace dimensions (among other things) are the relevant variables, but current density is not. I hope by the end of this article you will see why. Here are four illustrations that will help you understand this.
1. Current Density Is Not an Independent Measure
We can understand that the change in trace (and via) temperatures are a function of other variables. Thus, we can formulate the following as two possible relationships (all other things equal). Let:
C = current
J = current density
w = trace width
th = trace thickness
?T = change in trace temperature
Then, we can suggest the following:
Equation 1: ?T = fn(C, w, th)
Equation 2: ?T = fn(J, w, th)
Now, the question is, “Are both of these relationships true, or, if not, is either one true?” We know from the extensive experimental evaluations reported in IPC-2152 that Equation 1 is true, so is Equation 2 also true? From Equations 1 and 2, it follows that:
Equation 1a: C = fn(?T, w, th)
Equation 2a: J = fn(?T, w, th)
To read this entire article, which appeared in the September 2020 issue of Design007 Magazine, click here.
Suggested Items
Real Time with… IPC APEX EXPO 2024: Understanding Objective Evidence in Manufacturing Processes
05/07/2024 | Real Time with...IPC APEX EXPOGraham Naisbitt explains the importance of objective evidence in manufacturing processes, debunking the common misconception that the ROSE test is a cleanliness test. He also discusses the introduction of Rev J, a requirement for measuring ionic contamination on circuit assemblies, and the challenges in accurately measuring contamination. Alternative methods like ion chromatography and the need for updating standards like the ROSE test are mentioned.
Real Time with… IPC APEX EXPO 2024: My Role as a Technology Solutions Director
05/02/2024 | Real Time with...IPC APEX EXPOPeter Tranitz, senior director of technology solutions at IPC, shares insights into his role as the design initiative lead. He details his advocacy work, industry support, and the responsibilities of the design initiative committee. The conversation also covers the revamping of standards, the IPC Design Competition, and the implementation of design rules in software tools.
HQ NextPCB of HQ Electronics Debut on the International Stage for Electronics Manufacture at IPC APEX 2024
05/01/2024 | PRNewswireHQ NextPCB of HQ Electronics, a leading Chinese-based multilayer PCB manufacturer and assembly house showcased its industrial prowess on the international stage for the first time at the IPC APEX Expo 2024.
IPC's Vision for Empowering PCB Design Engineers
04/30/2024 | Robert Erickson, IPCAs architects of innovation, printed circuit board designers are tasked with translating increasingly complex concepts into tangible designs that power our modern world. IPC provides the necessary community, standards framework, and education to prepare these pioneers as they explore the boundaries of what’s possible, equipping engineers with the knowledge, skills, and resources required to thrive in an increasingly dynamic field.
North American EMS Industry Down 4% in March
04/29/2024 | IPCIPC announced the March 2024 findings from its North American Electronics Manufacturing Services (EMS) Statistical Program. The book-to-bill ratio stands at 1.31.