-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueThe Essential Guide to Surface Finishes
We go back to basics this month with a recount of a little history, and look forward to addressing the many challenges that high density, high frequency, adhesion, SI, and corrosion concerns for harsh environments bring to the fore. We compare and contrast surface finishes by type and application, take a hard look at the many iterations of gold plating, and address palladium as a surface finish.
It's Show Time!
In this month’s issue of PCB007 Magazine we reimagine the possibilities featuring stories all about IPC APEX EXPO 2025—covering what to look forward to, and what you don’t want to miss.
Fueling the Workforce Pipeline
We take a hard look at fueling the workforce pipeline, specifically at the early introduction of manufacturing concepts and business to young people in this issue of PCB007 Magazine.
- Articles
- Columns
Search Console
- Links
- Media kit
||| MENU - pcb007 Magazine
How to Streamline PCB Thermal Design
April 1, 2015 | John Parry, Mentor Graphics CorporationEstimated reading time: 2 minutes

Thermal issues with a PCB design are mostly determined during the component selection and layout phases. After this point, only remedial actions are possible if components are found to run too hot. Addressing thermal issues early in PCB design, starting at the system or enclosure level to understand the flow environment critical for air-cooled electronics, can streamline the process. Assumptions about the airflow uniformity in early design that subsequently prove unachievable can have a disastrous effect on the commercial viability of the product and meeting the market window.
Begin Before Placement and Layout
Substantial work can be done well before layout is completed within the electrical design flow. A simple representation of the enclosure can provide information about the air flow profile over the board. Start by smearing the total board power over the total board surface, which will provide a temperature map that will show any hot regions that are caused by a badly distributed air flow. Treat the board as a block with an isotropic conductivity of between 5 W/mK and 10 W/mK to optimize enclosure-level air flow ahead of the PCB design.
Components inject heat locally into the board so the heat flux density into the board below a component will be higher than the average for the board. As a result, the local board temperature will be higher than that predicted in the simulation. Refine the model before using the board temperature to estimate component temperatures. If the board temperature at any point is close to the maximum component case temperature, this limit will be exceeded once the component heat sources are represented discretely.
Guesstimate Component Power
At this stage, make a best-guess estimate of the individual power budgets for the main heat dissipating components that will be used in the design and the approximate size of those packages. This will enable describing them as footprint heat sources in the simulation, smearing the remainder of heat uniformly over the board surface.
Before Selecting the Package, Use 3D Component Models
Include some form of 3D component model in the simulation before the component selection is finalized. By feeding the thermal results back before this milestone is reached, the thermal performance will more likely be considered in the package selection criteria. Some ICs are available in more than one package style, and not all package styles perform equally well from a thermal point of view. The need for a heatsink later may be eliminated by appropriate package selection.
Component temperature, either in the form of a case temperature or junction temperature depending on how the manufacturer has specified the component, is the key measure used to indicate whether the design is thermally acceptable.
Editor's Note: This article originally appeared in the March issue of SMT Magazine.
Suggested Items
Bridging the Gap Between PCB Designers and Fabricators
04/03/2025 | Stephen V. Chavez, Siemens EDAWith today’s advanced EDA tools, designing complex PCBs in the virtual world does not necessarily mean they can be built in the real world. This makes the relationship between a PCB designer and a fabricator pivotal to the success of a project. In keeping with solid design for manufacturing (DFM) practices, clear and frequent communication is needed to dial and lock in design constraints that meet expectations while addressing manufacturing concerns.
IPC APEX EXPO Newcomer: Faith DeSaulnier of TTM Technologies
04/03/2025 | I-Connect007 Editorial TeamDuring the Newcomer’s Welcome Reception at IPC APEX EXPO, the I-Connect Editorial Team spoke with several first-time attendees. The following is our interview with Faith DeSaulnier, a process engineer based at TTM Technologies’ facility in Forest Grove, Oregon.
Ansys Semiconductor Solutions Certified by TSMC for Reliable, Accurate Analysis of Evolving Chip Designs
04/03/2025 | PRNewswireAnsys announced that PathFinder-SC is certified as a new ESD analysis solution for customers designing with TSMC's N2 silicon process technology. PathFinder-SC delivers a novel verification solution that provides superior capacity and performance, easily accommodating large designs in the cloud.
Real Time with... IPC APEX EXPO 2025: Insights into PCB Design and Manufacturing with Polar Instruments
04/03/2025 | Real Time with...IPC APEX EXPOErik Bateham discusses Polar's latest book, which enhances insights for PCB designers and manufacturers. The book, "The Designer's Guide to... More Secrets of High-Speed PCBs," features a guest chapter on 2D via design modeling. Erik highlights the industry's shift towards UHDI and the challenges in measuring at micron levels.
Connect the Dots: Stop Killing Your Yield—The Hidden Cost of Design Oversights
04/03/2025 | Matt Stevenson -- Column: Connect the DotsI’ve been in this industry long enough to recognize red flags in PCB designs. When designers send over PCBs that look great on the computer screen but have hidden flaws, it can lead to manufacturing problems. I have seen this happen too often: manufacturing delays, yield losses, and designers asking, “Why didn’t anyone tell me sooner?” Here’s the thing: Minor design improvements can greatly impact manufacturing yield, and design oversights can lead to expensive bottlenecks. Here’s how to find the hidden flaws in a design and avoid disaster.