Tag Archives: PCB

Technical Discussion of ATS Telecom PCB solution

Last year, Advanced Thermal Solutions, Inc. (ATS) was brought in to assist a customer with finding a thermal solution for a PCB that was included in a data center rack being used in the telecommunications industry. The engineers needed to keep in consideration that the board’s two power-dissipating components were on opposite ends and the airflow across the board could be from either side.

Telecom PCB

The PCB layout that ATS engineer Vineet Barot was asked to design a thermal solution for included two components on opposite ends and airflow that could be coming from either direction. (Advanced Thermal Solutions, Inc.)

The original solution had been to use heat sinks embedded with heat pipes, but the client was looking for a more cost-effective and a more reliable solution. The client approached ATS and Field Application Engineer Vineet Barot examined the problem to find the best answer. Using analytical and CFD modeling, he was able to determine that ATS’ patented maxiFLOW™ heat sinks would provide the solution.

Vineet sat down with Marketing Director John O’Day and Marketing Communications Specialist Josh Perry to discuss the challenges that he faced in this project and the importance of using analytical modeling to back up the results of the CFD (computational fluid dynamics).

JP: Thanks for sitting down with us Vineet. How was the project presented to you by the client?
VB: They had a board that was unique – where it would be inserted into a rack, but it could be inserted in either direction. So, we faced a unique challenge because airflow could be from either side of the board. There were two components on either side of the board, so if airflow was coming from one side then component ‘A’ would get hot and from the other side then component ‘B’ would get hot. The other thing was that the customer, who is a very smart thermal engineer, had already set up everything and he was planning on using these heat sinks that had heat pipes embedded in them. The goal was to try and come up with a heat sink that would do the same thing, hopefully without requiring the heat pipes.

JO: Can we talk for a second about the application? You mentioned that airflow was from either side, the board was going to be used in a data center or a telecom node?
VB: It was for a telecom company.

JP: Was there a reason he didn’t want to use a heat pipe?
VB: I think probably cost and reliability. We use heat pipes embedded in the heat sinks too, so it’s not a something we never want to use, but the client wanted to throw that at us and see if we had alternatives.

JP: Can you take us through the board and the challenges that you saw?
VB: As you can see from this slide, there are four main components and two of the hottest ones are on the edge. Airflow can be from right to left or left to right, so which one would be the worst-case scenario?

Telecom PCB

JO: From right to left, I think?
VB: Correct. This one is a straightforward one to figure out because not only is the component smaller but the power is also higher. Even though [air] can go both ways, there’s a worst-case scenario.

This was the customer’s idea – a straight-fin heat sink with a heat pipe and he put one block of heat pipe in there instead of two or three heat pipes that would normally be embedded in there. You can clearly see what the goal was. You have a small component in here, you want to put a large heat sink over the top and you want to spread the heat throughout the base of the heat sink. All the other components are also occupied by straight-fin heat sinks.

JO: Okay, at this point in the analysis, this is the rough estimate of the problem that you face?
VB: This is a straightforward project in terms of problem definition, which can be a big issue sometimes. This time problem definition was clear because the customer had defined the exact heat sink that they wanted to use. It’s not a bad heat sink they just wanted an improvement, cost-wise, reliability-wise.

This is the G600, which is the air going from left to right. The two main components are represented here and we want to make sure that the junction temperatures that the CFD calculated is lower than the maximum junction temperatures allowed, which they were. These heat sinks work. As we always like to do at ATS, we like to have two, independent solutions to verify any problem. That was the CFD result but we also did the analytical modeling to see what these heat sinks are capable of and the percent difference from CFD was less than 10 percent. Twenty percent is the goal typically. If it’s less than 20 percent then you know you’re in the ballpark.

(Advanced Thermal Solutions, Inc.)

(Advanced Thermal Solutions, Inc.)

JO: Do you use a spreadsheet to do these analytical modeling?
VB: HSM, which is our heat sink modeling tool, and then for determining what velocity you have through the fins, the correct way of doing this is to come up with the flow pattern on your own. You go through all the formulas in the book and determine what the flow will be everywhere or figure out what CFD is giving you for the fan curve and check it with analytical modeling. You can look at pressure drop in there, look at the fan curve and see if you’re in the ballpark. You can also check other things in CFD, for example flow balance. Input the flow data into HSM and it will spit out what the thermal performance is for any given heat sink. HSM calculations are based on its internal formulas.

JO: We effectively have a proprietary internal tool. We’ve made a conscious decision to use it.
VB: To actually use it is unique. Not everybody would use it. A lot of people would skip this step and go straight to CFD. We use CFD too but we want to make sure that it’s on the right path.

JP: What do you see as the benefit of doing both analytical and CFD modeling?
VB: CFD, because it’s so easy to use, can be a tool that will lead you astray if you don’t check it because it’s very easy to use and the software can’t tell you if your results are accurate. If you do any calculation, you use a calculator. The calculator is never going to give you a wrong answer but just because you’re using a calculator doesn’t mean that you’re doing the math right. You want to have a secondary answer to verify that what you did is correct.

JP: What was the solution that you came up with for this particular challenge?
VB: We replaced these heat sinks with the heat pipe with maxiFLOW™, no heat pipe needed. One of the little tricks that I used was to off-set the heat sinks a little bit so that these fins are out here and so the airflow here would be kind of unobstructed. And I set this one a little lower so it would have some fins over here, not much, that would be unobstructed. The G600 configurations worked out with the junction temperatures being below what the maximum requirement was without having to use any heat pipes for the main components. There is also a note showing that one of the ancillary components was also below the max. Analytical modeling of that was within 10-11 percent.

The final PCB layout with maxiFLOW heat sinks covering the hottest components on both ends of the board. (Advanced Thermal Solutions, Inc.)

The final PCB layout with maxiFLOW heat sinks covering the hottest components on both ends of the board. (Advanced Thermal Solutions, Inc.)

As you noted, this was the worst-case scenario, going from right to left and you can see because it’s the worst-case scenario this tiny little component here that’s 14 watts that’s having all this pre-heated air going into it, it’s junction temperature was exactly at the maximum allowed. That’s not entirely great. We want to build in a little bit of margin but it was below what was needed.

The conclusion here was that maxiFLOW™ was able to provide enough cooling without needing to use the heat pipes and analytical calculation agreed to less than 20 percent. We would need to explore some alternate designs and strategies if we want to reduce the junction temperature even further because that close to the maximum temperature is uncomfortable. The other idea that we had was to switch the remaining heat sinks, the ones in the middle, which are straight fin, also to maxiFLOW™ to reduce pressure drop and to get more flow through this final component.

(Advanced Thermal Solutions, Inc.)

(Advanced Thermal Solutions, Inc.)

JP: If you have an idea like that, is it something that you broach with the customer?
VB: They really liked the result. If this was a project where the customer said, ‘Yep, we need this,’ then we would have said here’s the initial result and we have an additional strategy. At that point the customer would have said, ‘Yeah this is making us uncomfortable and we need to explore further’ or they would have said, ‘You know what? Fourteen watts is a max and I don’t know if we’ll ever go to 14 watts or the ambient we’re saying is 50°C but we don’t know that it will ever get to 50°C so the fact that you’re at max junction temperature at the worst-case scenario is okay by us.’

JP: Do you always test for the worst-case scenario?
VB: It’s always at the worst-case scenario. It’s always at the max power and maximum ambient temperature.

JP: Was this the first option that we came up with, using maxiFLOW™? Were there other options that we explored?
VB: Pretty much. The way that I approached it was doing the analytical first. You can generate 50 results from analytical modeling in an hour whereas it takes a day and a half for every CFD model – or longer. These numbers here were arrived at with analytical modeling; the height, the width, the top width, were all from analytical modeling, base thickness to measure spreading resistance, all of that was done on HSM and spreadsheets to say this will work.

JP: Do you find that people outside ATS aren’t doing analytical?
VB: No one is doing it, which is really bad because it’s very useful. It gives you a quick idea if it’s acceptable, if this solution is feasible.

To learn more about Advanced Thermal Solutions, Inc. (ATS) consulting services, visit https://www.qats.com/consulting 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.

What Cost Reduction Strategies Make New Product Introductions Faster?

Getting to markets faster and in the most cost-effective way is the primary goal of today’s product development process. Choosing a thermal design engineering partner that understands that goal makes a company’s product realization process simpler and faster. There are number of strategies a company’s project engineers can use to save time and money in the design of an electronics cooling solution. Two of the most efficient methods are Virtual Engineering Demos (VED) and Thermal Load Boards (TLB).

VEDs make it possible for project engineers to remotely see an instrument, how it operates, ask questions about how it works, and, if the project is included in the demo, get data in real time about a design. In this method, a live demo is setup at a thermal design engineering partner’s laboratory. Whether the project is a PCB, a system, or another product type, it can be included in the VED and be run through the lab set-up.

Greg Wong

ATS engineer Greg Wong gives a live, online demonstration from the ATS research lab to a potential customer. (John O’Day/Advanced Thermal Solutions, Inc.)

Candlestick Sensor

ATS engineer Greg Wong sets up to demonstrate the ATVS-2020, Candlestick Sensors and StageVIEW Data Acquisition Software (DAQ) for measuring and analyzing temperature for an electronics board in this VED. (Advanced Thermal Solutions, Inc.)

VED in Lab

Equipment setup and live camera feeds are all part of a VED setup. (Advanced Thermal Solutions, Inc.)

As the project is analyzed, data is shown on the engineering partner’s computer screen, which is in turn broadcast in real time to the project engineers via a live video feed. The video feed simultaneously shows the demo and the software’s operation, while allowing bi-directional conversation between the engineering partner and the project engineers in one or more locations.


Screenshot showing data being recorded in stageVIEW. This information is available to the remote team. (Advanced Thermal Solutions, Inc.)

The advantages of this strategy to project engineers are:

• Quick evaluation of a design to determine if there is a need for new equipment in a project.
• No lag time in talking with a thermal design engineering partner about how to approach the thermal measurement of project
• Reducing the need to travel to a thermal design engineering partner’s lab.
• Faster response on lab testing, shortening the design cycle.

A Thermal Load Board (TLB) is another strategy for reducing the cost of a design, while getting a product to market faster. TLBs are created by a thermal engineering partner using a simple one- or two- layer non-populated PCB, heat sinks, thermally equivalent mock semiconductors and other mock components created with a 3-D printer.

TLB 3-D printing

Using these components a populated board is created that allows the testing of the heat sinks chosen for the project work and measurement of the airflow over the components and through the board. (Advanced Thermal Solutions, Inc.)

The thermal engineering partner is effectively creating a mock version of the functional board. The design of the TLB is based on the size and placement of the semiconductors and other components on the actual board, which is provided by the project engineers, and provides a cheaper and quicker means of producing a prototype for testing. The data from that testing will in turn expedite the design process and time to market.

This can be a very cost-effective method for doing heat sink characterization for the following reasons:

It reduces electronic system development cost.
o A system developer can focus on thermal issues very quickly instead of waiting for an expensive prototype to come out of the factory.
o Rather than using a potentially expensive project, testing on prototypes can determine design flaws without requiring a significant
o Because prototypes are less expensive, each iteration of a design can quickly go through an initial series of tests.
It reduces time to market.
o Valuable resources can be applied to engineering the best solution because a load board can generally be created in 1-2 weeks and at a
fraction of the cost of a full PCB.
It allows a physical testing very early in the design.
o Many times components on a PCB will obstruct air flow, requiring either costly design changes during NPI (new product introduction) or
requiring engineers to over-design a board and the thermal management solution, putting the product outside its cost objective.

After a thermal load board is created, the board is ready to be used:

Completed Load Board

A completed load board ready for testing. (Advanced Thermal Solutions, Inc.)

The heaters on the board can be powered up to dissipate the same level of power as the semiconductors they are meant to represent. Heat sinks can then be applied based on initial analysis done via integral modeling, mathematical modeling or through CFD (computational fluid dynamics). To test just air flow, heat sinks can even be created by 3-D printing.

Once populated with heat sinks, the board can be tested in a wind tunnel to see if the air flow will be sufficient. Wind tunnel testing methods include smoke flow visualization or water tunnel testing in order to examine air flow and ensure the most functional and cost-effective design is applied.

Getting to market faster and with the best possible design is very important in today’s product development process. Working with a thermal engineering partner, such as Advanced Thermal Solutions, Inc. (ATS), that offers Virtual Engineering Demos (VED) and Thermal Load Boards (TLB) will benefit a project’s bottom line and ensure a project’s successful completion. Project engineers will know that their design has proper thermal management early in the process, meaning that they will not have to over-design the project, which will save time and money in the long run.

Learn more about ATS and its capabilities as a thermal engineering partner for your next project by visiting www.qats.com or by calling 781-769-2800.


Thermal Load Board Design Considerations


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’ maxiFLOW Heat Sinks a Great Match with Altera’s Cyclone V

ATS’ new Heat Sink Selection Tool on www.qats.com allow engineers to match existing ATS heat sinks with specific applications from the top component manufacturers in the market.

Altera’s Cyclone® V FPGAs provide the industry’s lowest system cost and power, along with performance levels that make the device family ideal for differentiating your high-volume applications. You’ll get up to 40 percent lower total power compared with the previous generation, efficient logic integration capabilities, integrated transceiver variants, and SoC FPGA variants with an ARM®-based hard processor system (HPS).

Cyclone V (courtesy of Altera, http://www.altera.com/devices/fpga/cyclone-v-fpgas/cyv-index.jsp)

ATS has over 1,800 heat sinks that meet the specific application requirements of Altera. For example, the Altera Cyclone® V component part number 5CGXFC7D7F27C8NES has 17 cooling solutions, including ATS maxiFLOWTM high performance bga heat sink. maxiFLOWTM unique design provides thermal performance that is 30- 200% better than the conventional heat sinks. By combining maxiFLOWTM heat sinks with the Cyclone® V FPGAs, you can get the power, cost, and performance levels you need for high-volume applications including protocol bridging, motor control drives, broadcast video converter and capture cards, and handheld devices.

maxiFLOW heat sink results from the new Heat Sink Selection Tool

For mounting the heat sink to the pcb, these heat sinks are available with pre-assembled thermal interface materials and with the maxiGRIPTM heat sink attachment. maxiGRIPTM provides a steady, even pressure from the heat sink to the Cyclone® V with easy instillation and removal, eliminating the need to drill holes in the pcb.

Test out the new Heat Sink Selection Tool to view the full list of heat sinks specific to Altera components, along with the full list of component manufacturers that are compatible with ATS cooling solutions.