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Thermal Management Continues To Be Moving Target

With growing chip and PCB complexity, there is no question that thermal management is a moving target since advanced technologies and circuitry generate increasing amounts of heat. Consider that a lot of products in this day and age are small portable ones like smartphones and tablets. Small PCBs for these products are chock full of complex devices packaged in microBGAs and microCSPs ñ all of them generating considerable heat.

Certainly heat sinks are at the heart of heat dissipation, and more advanced models are getting fantastic results (see figure below). But at the end of the day, experienced PCB designers have to pull every trick in the book as well as dig into their ingenuity to come up with the right thermal management strategies.

When the PCB designer does the component placement during the layout phase, he or she needs to review the amount of power that is expected to be generated by these components and then, it’s time to perform the critical thermal analysis and develop a strategy for implementing it.

Thermal analysis involves defining areas of the board where extreme heat is being created. A straightforward rule is not to physically localize heat-generating components in one PCB location, but to spread out evenly on the board, if possible. An experienced CM or OEM PCB layout engineer in particular assures that digital and analog components are properly separated.

Here are some tips to keep you updated on thermal management for your products:

  • Keep in mind that SoCs on your PCBs have increasing amounts of analog circuitry that generate considerable heat and that important aspect must be carefully managed.
  • Extra special thermal analysis and management need to be applied to LED populated PCBs.
  • Assure that the right heat sink or heat sinks are designed in for your particular PCB project.
  • If your PCBs are mixed-signal, definitely ensure that your PCB designer avoids clustering analog components. Otherwise, the resulting adverse effects ripple throughout your system.
  • Make sure ground pour is used effectively and strategically apply thieving.
  • Create more solid planes as an excellent way to transfer the heat.

As part of the design process, the PCB designer should place special emphasis on the interface between heat sink and associated component or to the board itself because it is critical for effective thermal transfer. Normally, thermally conductive aluminum filled epoxy is used for bonding the fins of the heat sink to the component or to the board.

It’s important that the right kind of alloy or substrate is used for attaching those heat sinks. That requires considerable calculations and the right amount of aluminum or copper content within the epoxy and alloy substrate. The substrate material connects the heat sink to its associated component.