Tag Archives: Consulting

Discussion of Thermal Solution for Stratix 10 FPGA

An Advanced Thermal Solutions, Inc. (ATS) client was planning on upgrading an existing board by adding Altera’s high-powered Stratix 10 FPGAs, with estimates of as many as 90 watts of power being dissipated by two of the components and 40 watts from a third. The client was using ATS heat sinks on the original iteration of the board and wanted ATS to test whether or not the same heat sinks would work with higher power demands.

In the end, the original heat sinks proved to be effective and lowered the case temperature below the required maximum. Through a combination of analytical modeling and CFD simulations, ATS was able to demonstrate that the heat sinks would be able to cool the new, more powerful components.

ATS Field Application Engineer Vineet Barot recently spoke with Marketing Director John O’Day and Marketing Communications Specialist Josh Perry about the process he undertook to meet the requirements of the client and to test the heat sinks under these new conditions.

JP: Thanks again for sitting down with us to talk about the project Vineet. What was the challenge that this client presented to us?
VB: They had a previous-generation PCB on which they were using ATS heat sinks, ATS 1634-C2-R1, and they wanted to know if they switched to the next-gen design with three Altera Stratix 10 FPGAs, two of them being relatively high-powered, could they still use the same heat sinks?

Stratix 10 FPGA

The board that was given to ATS engineers to determine whether the original ATS heat sinks would be effective with new, high-powered Stratix 10 FPGA from Altera. (Advanced Thermal Solutions, Inc.)

They don’t even know what the power of the FPGAs is exactly, but they gave us these parameters: 40°C ambient with the junction temperatures to be no more than 100°C. Even though the initial package is capable of going higher, they wanted this limit. That translates to a 90°C case temperature. You have the silicon chip, the actual component with the gates and everything, and you have a package that puts all that together and there’s typically a thermal path that it follows to the lid that has either metal or plastic. So, there’s some amount of temperature lost from the junction to the case.

The resistance is constant so you know for any given power what the max will be. The power that they wanted for FPGAs 1 and 2, which are down at the bottom, was 90 watts, again this is an estimate, and the third one was 40 watts.

JP: How did you get started working towards a solution?
VB: Immediately we tried to identify the worst-case scenario. Overall the board lay-out is pretty well done because you have nice, linear flow. The fans are relatively powerful, lots of good flow going through there. It’s a well-designed board and they wanted to know what we could do with it.

I said, let’s start with the heat sinks that you’re already using, which are the 1634s, and then go from there. Here are the fan specs. They wanted to use the most powerful fan here in this top curve here. This is flow rate versus pressure. The more pressure you have in front of a fan, the slower it can pump out the air and this is the curve that determines that.

Stratix 10 FPGA

Fan operating points on the board, determined by CFD simulations. (Advanced Thermal Solutions, Inc.)

This little area here is sometime called the knee of the fan curve. Let’s say we’re in this area, the flow rate and pressure is relatively linear, so if I increase my pressure, if I put my hand in front of the fan, the flow rate goes down. If I have no pressure, I have my maximum flow rate. If I increase my pressure then the flow rate goes down. What happens in this part, the same thing. In the knee, a slight increase in pressure, so from .59 to .63, reduces the flow rate quite a bit.

Stratix 10 FPGA

CFD simulations showed that the fans were operating in the “knee” where it is hard to judge the impact of pressure changes on flow rate and vice versa. (Advanced Thermal Solutions, Inc.)

So, for a 0.1 difference in flow rate (in cubic meters per second) it took 0.4 inches of water pressure difference, whereas here for a 0.1 difference in flow rate it only took a .04 increase in pressure. That’s why there’s a circle there. It’s a danger area because if you’re in that range it gets harder to predict what the flow will be because any pressure-change, any dust build-up, any change in estimated open area might change your flow rate.

The 1634 is what they were using previously. It’s a copper heat pipe, straight-fin, mounted with a hardware kit and a backing plate that they have. It’s a custom heat sink that we made for them and actually the next –gen, C2-R1, we also made for them for the previous-gen of their board, they originally wanted us to add heat pipes to this copper heat sink, but I took the latest version and said, let’s see what this one will do. For the third heat sink, I went and did some analytical modeling to see what kind of requirement would be needed and I chose one of our off-the-shelf pushPIN™ heat sinks to work because it was 40 watts.

JO: Is the push pin heat sink down flow from the 1634, so it’s getting preheated air?
VB: Yes. This is a pull system, so the air is going out towards the fans.

Stratix 10 FPGA

CFD simulations done with FloTherm, which uses a recto-linear grid. (Advanced Thermal Solutions, Inc.)

This is the CFD modeling that ATS thermal engineer Sridevi Iyengar did in FloTherm. This is a big board. There are a lot of different nodes, a lot of different cells and FloTherm uses recto-linear grids to avoid waviness. You can change the shape of the lines depending on where you need to be. Sri’s also really good at modeling. She was able to turn it around in a day.

Stratix 10 FPGA

Flow vectors at the cut plane, as determined by CFD simulations. (Advanced Thermal Solutions, Inc.)

These are the different fans and she pointed out what the different fan operating curves. Within this curve, she’s able to point out where the different fans are and she’s pointing out that fan 5 is operating around the knee. If you look at all the different fans they all operate around this are, which is not the best area to operate around. You want to operate down here so that you have a lot of flow. If you look at the case temperatures, remember the max was 90°C, we’re at 75°C. We’re 15°C below, 15° margin of error. This was a push pin heat sink on this one up here and 1634s on the high-powered FPGAs down here.

Stratix 10 FPGA

JP: Was there more analysis that you did before deciding the original heat sinks were the solution?
VB: I calculated analytical models using the flow and the fan operating curves from CFD because it’s relatively hard to predict what the flow is going to be. Using that flow and doing a thermal analysis using HSM (heat sink modeling tool), we were within five percent. What Sri simulated with FloTherm was if a copper heat sink with the heat pipe was working super well, let’s try copper without the heat pipe and you can see the temperature increased from 74° to 76°C here, still way under the case temperature. Aluminum with the heat pipe was 77°; aluminum without the heat pipe was 81°, so you’re still under.

Basically there were enough margins for error, so you could go to smaller fans because there’s some concern about operating in the knee region, or you can downgrade the heat sink if the customer wanted. We presented this and they were very happy with the results. They weren’t super worried about operating in the knee region because there’s going to be some other things that might shift the curve a little bit and they didn’t want to downgrade the heat sink because of the power being dissipated.

Stratix 10 FPGA

Final case temperatures determined by CFD simulations and backed up by analytical modeling. (Advanced Thermal Solutions, Inc.)

JO: What were some of the challenges in this design work that surprised you?
VB: The biggest challenges were translating their board into a board that’s workable for CFD. It’s tricky to simplify it without really removing all of the details. We had to decide what are the details that are important that we need to simulate. The single board computer and power supply, this relatively complex looking piece here with the heat sink, and we simplified that into one dummy heat sink to sort of see if it’s going to get too hot. It all comes with it, so we didn’t have to work on it.

The power supply is even harder, so I didn’t put it in there because I didn’t know what power it would be, didn’t know how hot it would be. I put a dummy component in there to make sure it doesn’t affect the air flow too much but that it does have some effect so you can see the pressure drop from it but thermally it’s not going to affect anything.

JO: It really shows that we know how to cool Stratix FPGAs from Altera, we have clear solutions for that both custom and off-the-shelf and that we understand how to model them in two different ways. We can model them with CFD and analytical modeling. We have pretty much a full complement of capabilities when dealing with this technology.

JP: Are there times when we want to create a TLB (thermal load board) or prototype and test this in a wind tunnel or in our lab?
VB: For the most part, customers will do that part themselves. They have the capability, they have the rack and if it’s a thing where they have the fans built into the rack then they can just test it. On a single individual heat sink basis, it’s not necessary because CFD and analytical modeling are so established. You want two independent solutions to make sure you’re in the right ballpark but it’s not something you’re too concerned that the result will be too far off of the theoretical. For another client, for example, we had to make load boards, but even then they did all the testing.

To learn more about Advanced Thermal Solutions, Inc. consulting services, visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.

ATS welcomes engineering students from Tufts

Tufts University

Dr. Bahman Tavassoli of Advanced Thermal Solutions, Inc. gives a demonstration of a wind tunnel to Dr. Marc Hodes (left) and a group of students from Tufts University. (Advanced Thermal Solutions, Inc.)

On Friday, Oct. 14, Advanced Thermal Solutions, Inc. (ATS) welcomed Dr. Marc Hodes and a group of six mechanical engineering students from Tufts University to its Norwood, Mass. campus. The students learned about the company, its products, and took a tour of two of ATS’ four laboratories to see some of the testing equipment utilized by ATS engineers.

After a welcome from ATS founder, President and CEO Dr. Kaveh Azar, the students enjoyed a brief introduction from Marketing Director John O’Day about the company, its products, and the importance of thermal management in the design of today’s high-powered electronics.

The lab tours were led by Dr. Bahman Tavassoli, ATS Chief Technologist. First, he took the students into the Characterization Lab to demonstrate the BWT-104 open-loop wind tunnel and the CLWT-067 closed-loop wind tunnel. The students learned how ATS engineers use Candlestick sensors, thermocouples and the iQ-200 to measure air velocity, temperature, and pressure across a PCB using one system. There was also a thermVIEW Liquid Crystal Thermography unit set up, in which ATS engineers use infrared (IR) cameras to examine hot spots on a cold plate.

Tufts University

Students take a closer look at ATS testing equipment. (Advanced Thermal Solutions, Inc.)

Dr. Bahman Tavassoli

Dr. Tavassoli answers questions from Tufts University students. (Advanced Thermal Solutions, Inc.)

The Tufts students learned more than simply how the testing processes worked. They also learned why thermal management is an important consideration in the early stages of a design. Dr. Tavassoli and Dr. Hodes spoke of their professional experiences in the field of thermal engineering and where projects had gone wrong when thermal issues were not considered in the planning stages.

Dr. Azar also joined the students in the lab to show them the wicking material being used by ATS engineers in state-of-the-art vapor chamber designs.

Tufts University

ATS CEO, President and founder Dr. Kaveh Azar speaks with the student from Tufts in the Characterization Lab. (Advanced Thermal Solutions, Inc.)

After the Characterization Lab, the students were taken into the Electronics Lab and were given a demonstration of the Water Flow Visualization equipment. ATS engineers use the equipment to test how air will flow through a system.

The students asked numerous questions of Dr. Tavassoli to get a better idea of the important concepts of thermal engineering that were presented in the 90-minute visit to ATS. Now, the students will have the real-world applications that they saw at ATS in mind when learning the concepts of thermodynamics, thermal fluids, and more in their Tufts courses.

To learn more about Advanced Thermal Solutions, Inc., visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.

ATS Offers Arrow Customers a Half-Day of Free Access to its Thermal Characterization Lab


As part of the new distribution agreement between Arrow Electronics and Advanced Thermal Solutions, Inc., ATS is offering a half-day of free, no-obligation use of its unique Thermal Characterization Laboratory to Arrow customers. The Thermal Characterization Lab, located at ATS headquarters in Norwood, MA, allows engineers to perform thermal testing on heat sinks, fans and fan trays, PCBs, blades, enclosures, or complete systems. Experienced engineers, board and system designers can perform the tests themselves, or consult with an ATS thermal engineer at no cost during their 4 hours of laboratory time.

ATS’ Thermal Characterization Lab features a full range of research-quality instruments, including open and closed loop wind tunnels, for ambient and elevated temperature testing, all with PC-driven controls and automated data collection. The lab is also outfitted with a full array of the company’s sensor systems and thermocouples, which can be used to characterize electronic products under variable airflow and temperature conditions.

Liquid Crystal Thermography

In addition, the lab also features a JEDEC approved component thermal testing facility for conducting multitude of device level testing per JEDEC standards. The facility also provides a complete liquid crystal and IR thermography systems for non-invasive temperature mapping to 0.1oC with one micron-level spatial resolution; and a liquid cooling facility for complete testing and characterization of cold-plates, cooling effect and proof of concept testing.


“Most of today’s electronics have thermal situations that can turn into big problems if left alone. The easiest, lowest cost way to manage this is to conduct an accurate thermal characterization of the problem at hand,” said Kaveh Azar, Ph.D., President and CEO of Advanced Thermal Solutions, Inc. “If you have the right facility and associated know-how, you can often complete your test in a half-day, then you can readily assess what is the best thermal solution for your application. For engineers short on time and resources, we believe this free use of ATS’ Thermal Characterization Lab could be very helpful.”

Download the Brochure

To contact ATS for more information on this opportunity, please call 781-769-2800, email ats-hq@qats.com or visit www.qats.com.

New Consulting Project Subscription Plan

ATS has released a Consulting Project Subscription Plan (CPSP) for engineering services. From our corporate headquarters in Norwood, Massachusetts,we offers comprehensive thermal management analysis and design services for the telecommunications, medical, military, defense, aerospace, automotive, and embedded computing industries. The new plan allows ATS engineers to become an extension of your team for a pre-determined amount of hours, providing expert thermal and mechanical engineering consultation, design, simulation, testing and validation.

ATS Design Services

Services include Design, Simulation, Testing, Analysis & Prototyping

The CPSP includes the use of ATS thermal lab facilities and covers all projects approved by an authorized representative of subscribed customers. ATS thermal management analysis and design services encompass both experimental and computational simulations using proprietary tools and computational fluid dynamics software packages such as FLOTHERM and CFdesign.

Thermal Testing & Analysis

Thermal Testing & Analysis

The new subscription plan gives customers priority access to ATS engineering and manufacturing resources for all chip, board, enclosure, and system related projects. ATS studies the full packaging domain, including components, circuit boards (PCBs), shelves, chassis, and system packaging.

Consulting capabilities include:

– heat sink, board and fan characterization

– heat sink design and optimization

– PCB & fan tray design and optimization

– liquid cooling design

– prototyping of heat sinks and complete cooling systems

– wind tunnel testing of components, PCBs, chassis and enclosures

ATS offers rapid prototyping of machined parts and cooling systems from its US facilities. Sheet metal fabrication and cut heat sink prototypes are quickly provided from international partners.

Liquid Crystal Thermography

Liquid Crystal Thermography

ATS believes that customers who wish to remain competitive should consider a design-to-suit opportunity solution first. Contrary to common perception, this proves to be less expensive to the customer in the long run, because of the ensuing gain in product efficiency and compatibility. Working side-by-side with customers worldwide, ATS engineers provide tailored solutions to thermal and mechanical packaging challenges on real projects with real schedules.

To learn more about the consulting project subscription plan, call 781-769-2800, email ats-hq@qats.com, or visit www.qats.com.

ATS Design Services Contacted for ECL’s New Recycled LED Street Light

Eco City Lights (ECL), a leading supplier of commercial and industrial LED lighting products, recently contacted ATS design services for help in solving thermal challenges on a newly developed application.

ATS performed a full thermal analysis on ECLs retro-fit solution for cobra head street lights. Services provided by ATS included simulation, validation and reporting for the heat sink, enclosure and system level applications. Experimentation was done in order to validate and optimize the current design and the thermal solution. Using IR Technology and multiple sensors throughout the fixture, LED, heat sink, and power supply, testing was performed to determine the true temperatures of the output and enclosure parameters. After numerous studies were conducted, in addition to reviewing 3D CAD models of the enclosure and application components, ATS was able to successfully analyze the existing thermal management solution for the retro-fit street light.

ATS performed testing and analysis on the LED application

ATS performed testing and analysis on the LED application

Eco City Lights felt it was most important to find a thermal management company to evaluate, analyze, and comment on our led lighting solutions. “After researching our options ECL determined that ATS was the best qualified to handle our project. After personally visiting with Joe Gaylord of ATS and talking with their engineers, we now have a product line that is thermally tested, proven, and cost effective. As our company continues to grow, we will be adding addition products and look forward to working with ATS in the future” said Ken Moeller, President of Eco City Lights.

ECL's Cobra Head Street Light

ECL’s Cobra Head Street Light

Eco City Lights LED products are used in street, sidewalk, parking lot and warehouse applications for municipal, government, and commercial enterprises. It is crucial that the LEDs thermal performance is maximized, ensuring product reliability and an extended lifespan. The new recycled LED streetlight module is proven to save customers over 60 percent of energy consumptions costs, providing long lasting, low maintenance, and energy efficient LED lighting.

From its computational facilities and thermal/fluids laboratories in Massachusetts, ATS specializes in providing thermal analysis, mechanical and design services for the telecommunications, networking, medical, aerospace, defense, embedded computing, and automotive industries with high performance electronic products. To learn more about ATS Design Services, call 781-769-2800, email ats-hq@qats.com, or visit www.qats.com.