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How to Streamline PCB Thermal DesignApril 1, 2015 | John Parry, Mentor Graphics Corporation
Estimated 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.
RS Group Selects Siemens' EDA Simulation Technology for New Cloud Native DesignSpark Circuit Simulator12/05/2023 | PRNewswire
Siemens Digital Industries Software announced that the RS Group plc, a global provider of product and service solutions to more than 1.1 million industrial customers, has selected Siemens as its strategic electronic design automation (EDA) provider for its new, cloud native, DesignSpark Circuit Simulator tool – empowering users to streamline the design process.
EMA Design Automation to Spin-Off IP & Services Group to Enable Digital Transformation for the Entire CAD Industry12/04/2023 | EMA Design Automation
EMA Design Automation, the world's premier EDA VAR, is spinning off their IP, content, and services group as a new company named Accelerated Designs, LLC with a focus on CAD agnostic solutions.
SINBON Electronics, a provider of integrated solutions for electronic component design and manufacturing, recently obtained UL certification for its NACS (The North American Charging Standard) AC/DC charging cable. SINBON is the first electronic design service provider in Greater China to obtain this certification, and the first batch of charging cable orders has been shipped this week.
Cadence Signoff Solutions Empower Samsung Foundry’s Breakthrough Success on 5G Networking SoC Design12/01/2023 | Cadence Design Systems, Inc.
Cadence Design Systems, Inc. announced that Samsung Foundry successfully taped out a 5G networking SoC design on the Samsung 5LPE technology using the Cadence® Quantus™ Extraction Solution and Tempus™ Timing Solution.
There are many ways, dozens to be sure, and most likely many more, to streamline a PCB design. My goal here is to pick a single-digit number of rules to abide by, that can be reasonably adhered to, and provide some bang for the buck. These rules are meant to reduce design scope creep, avoid PCB respins, and improve production yields.