Category Archives: semiconductor

ATS’ Standard Board Level Heat Sinks for PCB

We’ve just released our new line of standard board level heat sinks. These stamped heat sinks are ideal for PCB application, especially where TO-220 packages are used. Available now through Digi-Key Electronics​ or at this link from ATS http://www.qats.com/eShop.aspx?produc…

 

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Are Your Heat Sinks and Thermal Management Strategy for Your Target Seminconductors Optimized or Deadended?

By virtue of the fact that ATS is a provider of heat sinks and thermal management solutions to electronics, much of work is target at the junction temperature of semiconductors. We work with a lot of suppliers in this space, most recently Intel’s Sandybridge. Which leads me to the reason for addressing this topic.

Are Your Heat Sinks and Thermal Management Strategy for Your Target Seminconductors Optimized or Deadended?

Of all the semiconductor providers works with, ATS has done a great deal of work with Caviuim, TI and Freescale. It’s not that their processors are unusually hot, it’s that these firms recognize that ATS does a great job of optimizing a thermal design. Our case studies show a wide range of applications and successes in this optimization.

With Cavium, ATS is a thermal development partner. We’ve tackled a number of difficult designs with them and with Cavium customer’s whose design elements create very dense, high performance products but in some small and low air flow applications.

ATS has two off-the-shelf stocks solutions for Cavium that can be used as design starting points, The ATS-691-C2-R1 offers up a thermal resistance of .6 C/W at 200 LFM and the ATS-725-C1-R1 offers up a thermal resistance of 2 C/W at 200 LFM.

Compilers Come to the Rescue in Thermal Management

Generally when we think of thermal management here at ATS, we think of it in terms of hardware. We consider heat pipes or heat sinks. We look at air flow and it’s direction. We consider materials and if their thermal conductivity is sufficient for a project or not. But that’s not the only part of the equation. Software is as well. And not just software for thermal modeling, but in terms of controlling semiconductors to reduce the thermal load in a system.

The key here is temperature aware compiling for VLIW (very long instruction word) processors. By properly grouping instructions in a CPU, compiler developers can help reduce the overall thermal load in a system. They do this by grouping as many instructions as possible in parallel, thereby minimizing the CPU workload and it’s peak temperature. There are a couple of techniques that have been published in research papers that we want to make our readers aware of.

The first is the technique of TempIB or Temperature Aware Binding Technique. This approach was developed by Benjamin Carrion Schafer, Yongho Lee, and Taewhan Kim at the School of Electrical Engineering and Computer Science Seoul National University, Korea. This technique:

effectively binds the instructions executed in parallel to the coolest possible functional units for a given fixed schedule. It generates, for each instruction in a scheduled instruction word, a priority queue of the coolest functional units that can execute the instruction, and rebinds it to the coolest possible unit, considering the temperature as well as the power consumed by the instruction.

Tests by the team show that temperature can be lowered almost 13% using this technique in thermal management. You can read their paper at this link: “Temperature-Aware Compilation for VLIW Processors“.

Another approach by researchers Madhu Mutyam, at the International Institute of Information Technology, Hyderabad, India and Feihui Li, Vijaykrishnan Narayanan, Mahmut Kandemir, and Mary Jane Irwin at Pennsylvania State University uses

a compiler-based approach to make the thermal profile more balanced in the integer functional units of VLIW architectures. For balanced thermal behavior and peak temperature minimization, we propose techniques based on load balancing across the integer functional units with or without rotation of functional unit usage.

You can read their work at this link, “Compiler-directed thermal management for VLIW functional units

Using software in this fashion may not be the standard approach to thermal management, but, adding it into the mix of strategies for electronics cooling, it can clearly help the overall goal.

How to use silicon to create a cost effective and thermally effecient microchannel heat sink

As liquid cooling technology is more readily adopted in electronics thermal management, particularly where very high heat fluxes are involved, there is a push to develop more efficient and cost effective cold plates to transfer device heat into the liquid cooling loop.   More than twenty years ago, Tuckerman and Pease pioneered the notion of microchannels for high-capacity cooling.  They noted that one particularly effective design would be to carve microscale channels into a piece of material.   The local heat transfer coefficient increases with the decrease of channel size and heat transfer would increase as more surface area is generate.

How do you create a cost effective and thermally efficient microchannel heat sink from this?   Click to ATS’s free “how to do it” paper by ATS’s Thermal Team, by visiting this link, “Using Silicon Microchannel Heat Sinks for Thermal Management

Handsets & smartphones working at full power are thermally hot; can a designer do anything to cool them?

If you’ve ever had a case of a hot hand from holding your smartphone or cell phone then you know that these small systems have thermal challenges as much as any large system. In fact, those challenges may be greater since there are limited options to cool such devices. Rob Rovetta, VP of Products, Quantance Inc, wrote an interesting editorial on this topic that’s well worth a read. In his editorial he notes such alarming facts as:

Thermal images of a high-speed USB data card with the plastic case removed, measured at room temperature and operating at peak transmit power shows a PA case temperature of greater than 91 degrees celsius (196 degrees fahrenheit).

and

Similar measurement for a smart phone, also with the plastic case removed, measured at room temperature, and operating at peak transmit power show a PA temperature to be greater than 86 degrees celsius (189 degrees fahrenheit). Clearly, the PAs used in today’s data cards and smartphones are one of the hottest items in the device and thus a primary cause for consumer complaints about heat. It is also worth noting that the operational specification for these PAs states the maximum case temperature should be limited to 90 degrees celsius, so even under fairly benign conditions, the PA is already being pushed to its thermal limit.

Rob offers some suggestions to get at the root issue in his editorial.

Quantance is in the business of creating low power RF technologies, but, Rob’s views are still valuable. As designers, we owe it to users to create the most thermally safe products that we can. Rob’s editorial gives food for thought in this area. Have a read by clicking to, “Reality Check: The heat is on; increasingly higher speeds introduce thermal challenges in mobile data devices