Trouble in Your Tank: Organic Addition Agents in Electrolytic Copper Plating
It’s Only Common Sense: Selling During an Economic Downturn
Marcy’s Musings: Can You Hear the Voices?
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.
Share on:
Suggested Items
Siemens, TSMC Extend Collaboration to Drive Semiconductor Design Innovation
04/25/2025 | SiemensSiemens Digital Industries Software announced that the company has deepened longstanding collaboration with TSMC to drive innovation in semiconductor design and integration, enabling mutual customers to tackle the challenges of next-generation technologies.
Ansys Strengthens Collaboration with TSMC on Advanced Node Processes Certification and 3D-IC Multiphysics Design Solutions
04/24/2025 | PRNewswireThrough continued collaboration with TSMC, Ansys announced enhanced AI-assisted workflows for radio frequency (RF) design migration and photonic integrated circuits (PICs), and new certifications for its semiconductor solutions. Together,
Autodesk Donates $4.3 Million to Cornell University to Prepare students for an AI-powered future
04/24/2025 |Autodesk announced a $4.3 million gift to Cornell University’s College of Engineering and College of Architecture, Art, and Planning (AAP) to help prepare students for the future of work in an increasingly AI-driven world. The investment will fund a new Autodesk Cornell Engineering Design and Make Space in Upson Hall.
Driving Sustainability in PCB Design
04/24/2025 | Marcy LaRont, I-Connect007Filbert (Fil) Arzola is an electrical engineer at Raytheon. He’s smart, entertaining, and passionate about PCB design. As it turns out, he’s also passionate about “Mother Earth,” as he calls her. Born and raised in Southern California, he freely admits that he turns the water off when he brushes his teeth and yells at his brother for throwing batteries in the garbage. But when looking at the issue of sustainability and PCB design, he urges his audiences to ponder what sustainability looks like. Can PCB designers, he asks, make any impact on sustainability at all?
Real Time with... IPC APEX EXPO: Silicon Geometry's Signal Integrity Impact on PCBs
04/24/2025 | Marcy LaRont, I-Connect007At IPC APEX EXPO 2025, Kris Moyer addressed the importance of understanding the impact of silicon geometry reduction on signal integrity and PCB performance. Kris says signal integrity considerations are necessary for so many designs today, regardless of clock frequency. He discusses valuable insights from attendees regarding embedded resistor technology and the effects of radiation on smaller silicon features in aerospace applications.