Category Archives: heat sink

Aluminum heatsink design uses passive cooling for high end graphics but don’t forget about your chassis fan strategy

Posted on June 29, 2010 by | Leave a comment

At ATS we’ve long been proponents of pushing the limits of thermal management using air. Why? No one wants truly wants to use liquid cooling in their computers be they workstations, servers, telecommunication servers or any other compute engines. Plumbing is something most engineers want to avoid. So our team applauded the release of Sapphire’s passive heatsink cooled graphics card, their HD5670.

The key thing to note on this card thermally is the unique geometry of the aluminum heatsink, aluminum heatpipe and fins. Thin and compressed to their graphics card, the PCI card’s silhouette requires only one X16 lane graphics slot. Sapphire doesn’t mention recommended air flow but they do suggest for best cooling performance, a chassis installed with at least one 120mm or 90mm fan is required.

Our team thought this design was well done, and a great application for passive heatsink cooling. Some thoughts we had included:

First, the required air flow amount and air flow velocity are key for a proper thermal management solution. These will be a function of what else you have in your chassis of course, CPU, memory, disk drives etc. A key critical point is do not block the air flow to known hot components and boards in your chassis. This is a common mistake we see at ATS be it computing or telecommunications. We’ve done a write up on how to choose a fan for your computer chassis on our blog, you can read it by visiting, “Five Basic Steps When Designing for a Cooling Fan Thermal Management”

Second, whether your fans are at the air inlet or outlet makes a difference and that needs to be considered. Always mount your cooling fans on the inlet side of your electronics chassis. This allows you to direct the highest velocity airflow to the areas of greatest need. In our example here, the Sapphire graphics card and your CPU (many thanks to Tony Koryban for his wisdom on fan placement)

With creative designs like Sapphires and the correct choice and placement of fans, air cooling continues to be an excellent choice for many thermal management problems. If you need help designing such a passive heatsink approach, drop some mail to us at [email protected]

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Posted in heat pipe, heat sink, thermal management

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ATS Heatsinks designed for Freescale’s QorIQ quad core processors including the new P3041

Posted on June 22, 2010 by | Leave a comment

ATS has a line of heatsinks and heatsink clips just for Freescale’s QorIq family of quad core processors.   We announced the family back in February.  Freescale just today announced an addition to their line, the FCBGA packaged P3041.  Before we talk about what ATS has, let’s read a bit of what Freescale’s new addition is about from their press release as seen at Design & Reuse Magazine:

The new QorIQ P3041 expands the reach of Freescale’s P4 platform into lower power applications. Manufactured in 45nm silicon-on-insulator process technology, the P3041 offers optimal integration and new intellectual property that delivers improved functionality for end products. The P3041 processor integrates four e500mc cores based on Power Architecture® technology running up to 1.5 GHz at less than 12 watts, and delivers about 2.5 DMIPS/MHz. Key features include a three-level cache hierarchy for optimized latencies, a hardware hypervisor for robust support of multiple operating systems within the device, a trusted boot architecture to ensure code is not tampered with or reverse engineered, efficient data path handling, and improved Serial RapidIO and SATA IP.

ATS’s family of heatsinks for Freescale’s QorIQ family features:

  • Thermal resistance as low as 1.5 C/W
  • Heatsink clips that allow the use of phase change material for superior chip to heatsink conductivity
  • Can be used for applications that require BGA heatsink or LGA heatsink.

We’ve included a presentation here to give you more information.  Or you can visit qats.com to purchase, request samples or learn even more.

[slideshare id=2323212&doc=atsmaxiflowandmaxigriptechnicaldatajuly09-091022155524-phpapp01]

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Why use active heat sinks? Here are some pros and cons to make an informed decision

Posted on June 17, 2010 by | Leave a comment

ATS has published two articles from the past on the topic of, “Why use active heat sinks” that we thought were worth putting some focus on to help our thermal management practitioners.  The fall back to an active heat sink can be alluring (what’s easier than slapping a cpu cooler fan onto your heatsink?  More air should cure all thermal management ills, no?)

The first article, “Active heat sinks direct air on hot chips but are they always the right choice?”  we published around the thought process on if an active heat sink was even necessary for your design.  It’s a good read to help prime your personal thought process and to think through your system design first.

The second article, “How system airflow affects active heat sinks: ATS ‘how to’ white paper“, covers the topic of the affect of your overall system airflow on your active heat sink. Cooling fans consist of an aggregate of airfoils, i.e., blades positioned around a hub that is driven by an electric motor. Due to their airfoil nature, a pressure differential is required across the blades to create the required flow. Therefore if this pressure differential is disturbed, fans will suffer performance degredation.

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Is CPU Cooling best done with a Copper Heatsink or Aluminum Heatsink?

Posted on June 16, 2010 by | 1 comment

The topic of whether a CPU heat sink should be a copper heat sink or aluminum heat sink comes up in every thermal management design. And the short answer as to which material to use is:

“It depends.”

There are many variables in designing the right heat sink, some of which include:

  • Thermal management cost budget relative to BOM cost
  • Orientation of boards (vertical or horizontal)
  • How much weight or stress can be applied to the target chip
  • How much keep out around a chip exists
  • Air flow to the chip
  • Air flow in and through the system (maybe you don’t need a heat sink at all as noted in an earlier ATS White Paper)
  • Component dimensions
  • Component height
  • Target junction temperature
  • Target case temperature

Let’s just focus on the material question though, copper heatsink vs. aluminum heatsink. Chris Soule, Engineering Director at Thermshield, has done a nice one page write up on the topic. Some of his key points include:

  • Pure copper has about two times the conductivity of aluminum but that inherent advantage is only helpful when
  1. Air Flow speeds are 800 LFM
  2. The hot spot on the CPU or other semiconductor is small in comparison to the size of the chip itself.
  • When air flow is 400 LFM or lower or the hot spot on the CPU or semiconductor is spread throughout the chip, then Aluminum is a better choice.
  • The cost of a copper heat sink is often up to three times the equivalent sized aluminum heat sink

In our labs here at ATS, we’ve found that if an aluminum heatsink by itself does not have the necessary thermal condutivity, then using phase change thermal interface material (such as those listed in our Thermal Interface Roundup Post) with the proper pressure applied can make the difference in cooling.

So which do you use? Copper or Aluminum? It depends on the variables noted including your budget. One thing is for sure, there is no clear, one sized fits all answer and the thermal engineer should carefully decide. Hopefully before the electrical design is complete!

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Posted in heat sink, Thermal Interface Material

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LED Thermal Management Company Uses New PCB Design as the LED Heat Sink

Posted on June 16, 2010 by | Leave a comment

We’ve talked a bit here at the ATS Thermal Blog about using a PCB as your heat sink. Tony Koryban specifically fielded a question on this topic in fact. Now, one of ATS’s friendly colleagues in the thermal management industry has invented a novel way to use the PCB as the LED heat sink itself.

SinkPAD Corporation, located in Anaheim, has launched it’s technology which:

… conducts heat out of the LED system (LED cooling) by enabling a direct thermal path between the LED and surrounding atmosphere, which eliminates thermal resistance introduced by the dielectric material in a traditional IMS PCB or MCPCB. The SinkPAD design completely removes the substance with the lowest thermal conductivity/highest thermal resistance from the structure. SinkPAD still uses a dielectric, but this dielectric isolates the metal base electrically and leaves it thermally connected. The thermal path should be electrically neutral within the LED package, i.e. Cree XLamp, Luxeon Rebel from Philips Lumiled, PhlatLight from Luminus, in order to solder the LED directly to the SinkPAD.

It’s pretty cool stuff and an exciting development for solid state lighting. You can learn more over at SinkPad’s site at www.sinkpad.com

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Posted in heat sink, LED

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