The brick DC-DC converter heat sinks offer a range of fin patterns, directions and profiles to match different height and weight restrictions and airflow patterns. All of these heat sinks are protected with a gold anodized finish.

Each heat sink is provided pre-assembled with a layer of Chomerics T766 Thermflow phase change thermal interface material to enhance heat transfer from brick to heat sink. All of these heat sinks also come with three sets of screws in lengths of 5, 6 and 8 mm for varied attachment situations. The heat sinks’ pre-drilled hole patterns fit all major DC-DC converter designs.

DC-DC converters are circuits which convert direct current (DC) from one voltage level to another. They are extensively used in electronic devices serving communications, computing, data storage, health care, industrial equipment, instrumentation and test and measurement. Heat sinks are typically required to keep the converters running within safe operating temperatures.

Advanced Thermal Solutions, Inc. has expanded its Massachusetts manufacturing facilities. This was necessary due to an increase in industrial orders and associated production requirements. The needs for metal and plastic parts and finished products have been growing as markets retool and expand, and buyers continually insist on higher quality, faster deliveries and larger volumes.

ATS expanded manufacturing services can provide contract manufacturing services on a fast, highest quality level. The Norwood facility will meet the needs of most global customers, from rapid prototyping and high volume manufacturing.

The enhanced facilities in Norwood, which is also the global headquarter for ATS, are fully equipped, environmentally responsible, and employ highly skilled staffers who work to extremely high professional standards. Multi-point inspections insure the highest quality manufactured products, from one-of-kind to multi-thousand part production orders.

ATS designs and builds for a wide range of industry requirements. Engineers and technicians manufacture for chassis-level integration, e.g. cooling hardware and other functionalities on network communication cabinets. The associates often design and fabricate stands, rack and display cabinets for retail and office environments.

Fabrication capabilities in metal and plastics include:
• Metal and Plastic Extruding
• Metal Stamping
• CNC Machining
• Metal Finishing
• Sheet Metal Stamping and Plastic Forming
• Plastic Welding

Besides its manufacturing facilities in Norwood, ATS operates factories in Futian, China, a thriving region of high tech manufacturing. The Futian facility is designed for making very high volumes of quality parts, as well as inventory and storage, and worldwide distribution services.

To learn more about ATS manufacturing capabilities, please visit: http://www.qats.com/Services/Manufacturing-Services/65.aspx

Most LEDs are designed in SMT (surface mount technology) or COB (chip-on-board) packages. In the new 1~8W range of surface mount power LED packages, the heat flux at the device’s thermal interface can range from 5 to 20 W/cm2. These AllnGaP and InGaN semiconductors have physical properties and limits similar to other transistors or ASICs (application specific integrated circuit). While the heat of filament lights can be removed by infrared radiation, LEDs rely on conductive heat transfer for effective cooling.

As higher powers are dissipated from LED leads and central thermal slugs, boards have changed to move this heat appropriately. Standard FR-4 technology boards can still be used for LEDs with up to 0.5 W of dissipation, but metallic substrates are required for higher levels. A metal core printed circuit board (MCPCB), also known as an insulated metal substrate (IMS) board, is often used underneath 1W and larger devices. These boards typically have a 1.6 mm (1/16 inch) base layer of aluminum with a dielectric layer attached. Copper traces and solder masks are added subsequently. The aluminum base allows the heat to move efficiently away from the LED to the system.

Increasing power density, a higher demand for light output, and space constraints are leading to more advanced cooling solutions. High-efficiency heat sinks, optimized for convection and radiation within a specific application, will become more and more important.

As with any semiconductor package, thermal resistance plays a significant role in the thermal management of LEDs. The highest thermal resistance in the heat transfer path is the junction-to-board thermal resistance (Rj-b) of the package [2]. Spreading resistance is also an important issue. Thermally enhanced spreader materials, such as metal core PCBs, cold plates, and vapor chambers for very high heat flux applications are viable systems to reduce spreading resistance. [3]

Linear heat sinks are available specifically for LED strips, such as OSRAM SYLVANIA’s DRAGONstick® linear LED strips, which are widely used in architectural lighting. For example,the maxiFLOW™ linear heat sink from Advanced Thermal Solutions, Inc., has a patented spread fin array that maximizes surface area for more effective convection (air) cooling, particularly when air flow is limited, such as inside display cases.

Round heat sinks are available specifically for round LED boards, which are used to replace halogen light bulbs, in applications such as spotlights and down lighting. A typical LED spotlight is shown in Figure 2 [5]. Here, a round QooLED© heat sink from Advanced Thermal Solutions is used for cooling three LEDs. The round heat sink has a special star-shaped profile fin design that maximizes surface area for more effective convection (air) and radiation cooling in the vertical mounting orientation, e.g., inside ceilings.

Active thermal management systems can be used for high-flux power LED applications. These include water cooling, two-phase cooling, and fans. Although active cooling methods may not be energy-justifiable for LEDs, reasons for using them include ensuring lumen output or maintenance-free operation, or to meet specific wavelength requirements.

Advanced Thermal Solutions, ATS, has released its fourth collection of technical articles from Qpedia, the company’s widely referenced Thermal eMagazine. This new volume presents 48 technically detailed, full-color articles that cover the widening spectrum of electronics thermal management.

The articles discuss many of today’s cooling approaches, from multilayer minichannel heat sinks to electro-osmotic pumps to thermoelectric coolers. Other features offer an informative look at special thermal management needs, including high altitude heat transfer, data center cooling, and defense electronics.

The new Qpedia book, Volume Four, also includes features on thermal grease, fans, cold plates, refrigeration systems and heat sinks. Further articles explain how to optimize thermal vias, use pool boiling for component cooling, and improve CFD modeling of PCBs for more effective thermal management.

 All articles in this useful collection are written and edited for engineer-level readers by the thermal and mechanical engineers from Advanced Thermal Solutions. The authors include Kaveh Azar, Ph.D., the company’s president and CEO; and Bahman Tavassoli, Ph.D., its chief technologist. Both Drs. Azar and Tavassoli are internationally recognized experts in the thermal management of electronics.

 This new fourth collection of Qpedia technical articles can be ordered from the ATS website: Qats.com. The three preceding volumes are also available. Each volume can be purchased separately and discounts are added to orders of multiple copies. See Qats.com for details.

IIn the paper, which appears in the company’s e-magazine,  ATS considers a liquid cooling system as a closed loop system with three major components: cold plate, heat exchanger and pump. The cold plate is typically made from aluminum or copper, and is attached to the device being cooled. The plate usually has internal fins which transfer heat to the coolant flowing through them. This fluid moves from the cold plate to a heat exchanger where its heat is transferred to the ambient air via forced convection. The final part of the cooling loop is the pump, which drives the fluid through the loop.

A series of equations is provided to predict the final temperature of the device being cooled. The first of these equates the surface temperature of this device with the product of the power dissipated by the device times the thermal resistance of the cold plate (and its thermal interface material), added to the temperature of the water entering the cold plate.

The sequence of calculations factors in specifications from the cold plate, heat exchanger and pump.  The result is a solution for the device temperature as a function of cold plate resistance. In the example cited by ATS, a cold plate thermal resistance of less than 18 degrees C/W is required to cool an Intel Xeon 5492 processor in a 25C temperature environment.

Liquid cooling is an important and expanding practice in the electronics industry. It is important to understand the impact on performance of all three major parts of liquid cooling loops (cold plate, heat exchanger and pump) to ensure an acceptable level of performance at the lowest cost.

Instructions for calculating load for liquid cooling systems are available on Qats.com in the pages of Qpedia, the thermal management emagazine from ATS. More information is also available by calling 1-781-949-2522.

Each Q2 webinar is planned for a Thursday afternoon (ET) late in the month. These are the second quarter topics for the ATS webinars:

April 26, 2012 at 2:00 p.m. ET

How to Perform and Understand Air Velocity Measurement within Electronics Systems

Participants will learn about the importance of measuring air velocity in a system, the instruments necessary for obtaining useful measurements and where these velocities should be recorded.

 May 24, 2012 at 2:00 p.m. ET

CFD as a Tool to Perform Heat Sink and System Modeling

Computational Fluid Dynamics (CFD) tools have become indispensable simulation tools, enabling design engineers to confront electronics cooling challenges on demand. Some tips and tricks are invaluable in performing these analyses. Among them: the simplest methods of preparing a CFD model; the best techniques for meshing; and how to model a system’s components, such as fans and perforated plates. Attendees will learn about common and not-so-common issues in CFD, and how to overcome them.

June 28, 2012 at 2:00 p.m. ET

Heat Sink Selection Made Easy

As heat dissipation needs for electronic devices rapidly grow, choosing the right heat sink the first time is essential. With so many application requirements and heat sink options, this can be a daunting task. In this webinar, attendees will learn about the importance of system airflow and its impact on heat sink design; attachment methods; and how to solve thermal design challenges.

 Seats at each of these webinars are free, but limited. Registration is available online at http://www.qats.com, or by calling 1-781-949-2522.

Pricing for a QoolPCB solutions is based on the number of heat sinks that a specific PCB requires for efficient thermal management.  For example, if thermal analysis and testing show that a PCB needs 10 heat sinks to operate afely, the fixed price for the heat sinks and hardware for a production volume of that PCB would be just $50 per board. For larger boards, or those with many hot components, the unit cost per heat sink is reduced.

Whether the solutions are for off-the-shelf heat sinks, custom designed, or a combination of both, the QoolPCB program from ATS provides it at fixed cost. QoolPCB eliminates separate costs for design, tooling, samples, verification and supply chain management. The program offers multiple benefits for companies looking to reduce their product development costs, speed time-to-market and ensure thermal reliability.

To participate, PCB developers simply provide 3D CAD models of their board layout, along with the technical specifications, including power dissipation of all board components. ATS performs a full thermal analysis of the PCB and develops a comprehensive cooling solution for each component on the board. Where possible, ATS engineers will specify existing heat sinks from a portfolio of more than 3000 off-the-shelf and application-specific designs and with in-stock attachment systems.

If any custom heat sinks are required to bring certain components within their manufacturer-designated running temperatures, ATS assumes all tooling charges and sample production costs, including any customized heat sink attachment hardware. In addition, ATS will perform all physical testing at its Thermal Characterization Laboratory, which features advanced open loop and closed loop wind tunnels, temperature and velocity measurement sensors and other analysis instrumentation, to verify the cooling design. All designs and performance reports are provided to customers, who can perform their own thermal analyses and verification studies using the ATS characterization lab and samples of the actual heat sink solutions at no extra cost.

More information about the QoolPCB thermal management program from ATS is available at: http://www.qats.com/Services/QoolPCB—PCB-Cooling-At-Fixed-Cost/57.aspx

One of the most popular methods uses some form of clip. These are low in price and easily applied. Smart engineering has led to clip systems that provide strong, even pressure well beyond the working life of the component. They hold their heat sinks tight even when dropped or shocked, but they can be unclipped manually whenever it’s necessary.

Clips that attach directly to the component provide an advantage over other clip types, (e.g. z-clips) in that no holes are required in the PWB.  The ATS maxiGRIP is an example of such an attachment.   maxiGrip uses a plastic frame clip that attaches directly to the component and provides a mounting platform for a custom spring clip (Figure 5).

The frame clip is installed, using a special tool which expands all four sides of the clip simultaneously, allowing the clip to be placed directly over the component package (A keep out area is usually required).  Once released, tabs on each side engage and secure the clip to the component, creating a secure mounting platform for the spring clip.  The spring clip, which is designed to provide a very precise load, is then installed to hold the heat sink in place, maintaining continuous pressure at the heat sink component interface.   The maxiGripTM assembly has a big advantage over other heat sink attachment methods in that it allows for the use of high performance phase change interface materials.

Extensive FEA and shock and vibration testing of the maxiGripTM assembly have been done to provide a carefully engineered heat sink attachment solution with a high-level of reliability.

 A typical thermoelectric module is manufactured using two thin ceramic wafers with a series of N and P doped bismuth-telluride semiconductor material sandwiched between them. The ceramic material adds rigidity and the necessary electrical insulation. The N type material has excess electrons, while the P type material has a deficit of electrons. One N and one P make up a couple.

 When a DC current is applied to the circuit, the thermoelectric module can work as a cooler or heater depending on the current’s direction. A thermoelectric cooler (TEC), or solid state heat pump transfers heat from one side of the device to the other side against the temperature gradient. Many products use thermoelectric coolers, including small refrigeration systems, CCD cameras, laser diodes and portable picnic coolers. They are also used in the thermal management of microprocessors, memory modules and other electronic devices.

Although a TEC provides a very simple and reliable solution for cooling devices, its poor thermal performance prevents its broader usage. Compared with traditional refrigeration systems, the coefficient of performance (COP) of a TEC is only about 1/5 that of a refrigeration system using a vapor compression cycle. Currently, the uses of TECs in electronics cooling are limited to systems that require temperature stability or sub-ambient operating conditions, or specially designed devices. Laser beam components and high energy optical modules are such examples.

The Kit is specifically for thermal management professionals in the LED lighting industry and for engineers who are responsible for ensuring the proper performance of LED designs.

Included in the Resource Kit are:

• LED Heat Transfer and Cooling Options:  Lighting the Way for LED Development

• Mentor Graphics Webinar (free registration required): Diagnosing and Solving Thermal Challenges in Next Generation LED

• ATS Case Study: Feasibility Study of an LED-Based Lighting System Using Analytical Modeling

• ATS Article: How to Cool High Power LEDs

• Clemens Lasance Lecture on LED Thermal Management:  Thermal Management for LED Applications: What is the Role of the PCB?

• Clemens Lasance, Michael Gay, Norm Berry, Richard A. Wessel on MCPCB’s for LED Applications:  MCPCB’s for LED Applications, Thermal Management Material Specifications

• Dr. Kaveh Azar Video Interview: LED Heat Sink Types and Applications

The free LED Cooling Resource Kit can be accessed at: http://qats.com/cms/free-thermal-management-led-lighting-resource-kit/

Here’s a brief list of our capabilities:

Material

• Aluminum
• Metals
• Plastics
• Stainless Steel

Our Norwood MA facility does the rapid prototyping and low volume production,  here is a list of our equipment:

Machining Center

Saws & Shears

What else we got?
We have lots of stuff to talk about, but, rather than discuss the parts and pieces of our rapid prototyping and high volume manufacturing, its’ better to talk about examples, and we’ll be doing some of that this week here on ATS’s blog.  In addition, we’ll be highlighting a very important engineering article on how to manufacture cold plates.

Consumer electronics are now being used in places that were once exclusive to business and military electronics. Products like Apple’s iPhone and iPad are sophisticated technologies with powerful processors housed in small spaces with restricted airflow. As a result, these devices, and others like them, are providing many new benefits, but they also bring higher thermal management needs. Attendees will learn the available cooling options, and important factors such as the importance of spreading resistance in component and system thermal management.

The webinar is going to be chock full of great information cooling consumer electronics.    The webinar is free and taught by Dr. Kaveh Azar, one of the worlds foremost authorities on heat transfer.  Click here to register: “Thermal Management of Consumer Electronics“

Use cases include:

• Consultants:   Are  you on premise with your client?  Once you understand your needs for a heat sink, use our heat sink design tool to get a product fast.
• Field Engineers:  If your in the field, taking notes on what heat sink to use might be impractical.   Use our heat sink design application to punch in the parameters for a heat sink and get it done right there.
• Students:  If your in the lab working on your next project, why not use our convenient application on your Android device to get our project that much quicker to completion

You say you use an iPhone?  Well, we have an App for that too!  Apple iPhone Heat Sink Design App

And for a more robust alternative to a thermocouple, consider ATS Spot Sensor,  you can learn more about our spot sensor at this link or get a quote at this link.

Thanks for your patience!

4 — Infrared Thermography

Infrared thermography works on the basis of the IR waves emitted from a heated surface. The infrared system captures the waves, and based on internal calibration converts them into temperature. The following are required for IR-based measurements:

• Infrared imaging system — The market offers a broad range, but a worthy system starts at around $30-70k. For IR microscopy (down to 5mm only-lower limit of IR wave-length), the system starts at $180k.
• Signal processing equipment.
• Knowledge of emissivity – if the test specimen must be coated with a known emissivity material.
• Calibration.

Figures 5a and 5b show a typical IR image of heat-emitting surfaces:

5a shows and IR image of a PCB in forced convection air flow[3]

5b shows and IR image of a PCB in forced natural convection air flow[3]

The following points are noteworthy when using an IR camera for temperature measurement:

• Application accuracy is a function of emissivity.
• The measurement situation must duplicate the actual environment, as far     as air velocity, temperature and air flow distribution are concerned.
• The IR camera is sensitive to reflected radiation.
• Carbon dioxide and water vapor absorb significant energy and may cause significant error.
• In an electronics application, surfaces typically have different emissivities thus, one must make the emissivity uniform before measurement of known emissivity (black paint or powder).
• In most IR equipment, the temperature readout is the average over an area. Therefore, temperature peaks may be ignored as the result of integration. To remedy the situation, better IR optics must be used to reduce the area where integration occurs.

5 — Optical Probes

Optical sensors are light-emitting devices that illuminate the test body with source radiation, and can detect reflected radiation, or simulated radiation such as fluorescence. Although not broadly used, optical probes are used at the die or component level. Figure 6 shows one such a probe.

Figure 6. Optical Probe For Surface Temperature Measure-ment — The Probe Either Touches The Surface Or Captures The Reflected light From A Fluorescent Treated Surface.

 6 — Liquid Crystal Thermography

LC thermography works on the basis of visible light reflected from a surface treated with the LC material. The system captures the reflected wavelengths, and based on internal calibration, converts them into temperatures. Liquid crystals (LCs) are cholesteric materials. When applied to a heated surface they realign and reflect light at a different wavelength. The reflected light shows the standard colors seen in a rainbow. Figure 7 shows the application of LCs on an IC.

Figure 7. Color display of liquid crystal applied on an IC. Blue reveals the circuit’s hottest point, and black shows that the temperature is outside the range of the crystal material [3].

The following are salient features of LC material:

• Liquid crystals are organic compounds that can be poured like a liquid, yet reflect light like a crystal.

• Changes in LC optical properties can be produced by externally applied fields (e.g., electrical, magnetic, and thermal).

• Cholesteric liquid crystals progressively exhibit all colors of the visible spectrum when heated over their event temperature range.

• Width and placement of the event temperature range can be controlled by selecting and mixing the appropriate liquid crystals.

• Liquid crystals are commercially available with event temperatures ranging from below 0^oC to 160^oC, with spans ranging from 1 to 50^oC.

An LC thermography system such as the one shown in Figure 8 can provide a very effective temperature-mapping system.

Figure 8:  The thermVIEW System for Macro and Microscopic (down to 1um) Surface Temperature Measurement[4]

Figure 9 shows a typical result of LC thermography at die level:

Figure 9. Temperature distribution across a memory chip (5 x 5 mm) at T_ambient = 25^oC, as shown using Liquid Crystal Thermography [3].

Like any other system for temperature measurement, LC thermography offers distinct advantages and disadvantages. One salient advantage of LC thermography is that it’s not dependent on surface emissivity. A second is that at micron and submicron levels, though not a trivial task, LC thermography allows easier and less costly temperature measurements while enabling 1µm or smaller spatial resolution. One disadvantage of LC thermography is that it is not a pick-up-and-measure system like IR. One must apply the calibrated liquid crystal material to a surface in order to perform the measurement. But, this is similar to the IR system, in that you need to make the surface emissivity uniform if the measured surface has multi-emissivity (e.g., a die or PCB).

In this article, we reviewed six different probes/techniques for temperature measurement. It would be a missed opportunity not to include a word on calibration. Irrespective of the types of measurement and sensors one uses, calibration is of utmost importance. Pay special attention to the calibration process and ensure that the sensors are properly calibrated. Further, one needs to ensure that the chosen sensor is suitable for the type of measurement. As Prof. Frank White states in his Viscous Flow book, “Bad data is worse than no data at all” [5].

To catch up on the series or read from the start, you can click to Part 1 of our series or click over to Part 2 of our series.

References

1. Klinger, D., Nakada, Y., Menendez, M., AT&T Reliability Manual, Van Nostrand Reinhold, 1990.
2. Azar, K., Thermal Measurement in Electronics Cooling, CRC Press, 1997.
3. Advanced Thermal Solutions, Inc., Tutorial Series, “Principles of Temperature Measurement”.
4. thermVIEW™ System, product of Advanced Thermal Solutions, Inc.
5. White, F., Viscous Fluid Flow, McGraw-Hill, 3^rd Ed., 2005.

If  you are in need of sensors for thermal measurement, click now to ATS’s sensor family.   To learn more about ATS ‘ thermVIEW liquid crystal thermal analysis system, click to thermVIEW System.   You can also email or call us with your questions on temperature measurement and one of our engineers will be happy to help you.  Email us at ats-hq@qats.com or call  us at 781-769-2800.

1 — Resistance Thermometer

With these sensors, the resistance of the sensing element changes with temperature. The sensors come in two primary forms: thermistors (lightly doped semiconductors) and metal resistors. Equations 3 and 4 represent the relationships between resistance and temperature for these two sensors, respectively:

Figure 1 shows a surface-mounted RTD (resistance temperature detector) that can be installed onto a surface for temperature measurement:

Figure 1: Surface mounted RTD (photo courtesy of RDF Corporation)

 The following must be considered when using these types of sensors:

1. The sensor (resistor) must be in intimate contact with the test specimen — solder or careful epoxy is recommended.
2. The sensor must be placed in an isothermal region — constant temperature over the sensor.
3. The resistor power dissipation (if in voltage mode) must be minimized to not impact the problem.
4. This sensor is suitable for part-level measurement as it can be embedded directly on the die.

2 — Thermocouples (TC)         

These sensors are far and away the most commonly used devices in the field. Wide flexibility and broad availability enable their use for a variety of temperature measurements. TCs work on the principle that bringing together two wires of different elements or alloys produces a voltage as a result of temperature. Equation 5 provides the governing principle for TCs:

Table 2 shows some of the typical TC types that are used in electronics thermal measurement.

Table 2: Thermocouple Types and Their Respective Voltage Outputs [2]

Of the TC types shown above, E, J, K and T are the most commonly used. Many thermocouple meters on the market can use all of these sensors interchangeably. That’s because the voltage output of these TCs is in the same range; hence, the internal electronics can be designed to accommodate each of them.

There are some unique features about each sensor type that one needs to know. For example:

• E-type —  Though accurate, has a limited range.
• J-type —  Should not be used in a humid environment, since the iron component of the TC will oxidize, resulting in erroneous output.
• K-type —  Though widely used, the voltage output can be negatively impacted if the wire kinks.
• T-type —  Can be an effective heat transfer medium, because of its copper component, either as a fin or a conductor.

It is also important to note that thermocouples measure temperature at the point where the two wires are connected. The smaller the junction, the more precise the temperature that is read. A large TC junction will result in the temperature being averaged over its entire area. Multiple junctions, as shown in Figure 2, will have the same impact. In Figure 2, the multi-junction created as a result of twisting the wires prior to spot-welding the ends (the TC below), creates a significantly larger junction. Whether measuring surface or fluid temperatures, the number reported by this TC will report an average temperature over a 2-3mm junction length.

Thermocouple errors can be attributed to the following areas:

• Poor junction connection
• Galvanic action
• Thermal shunting
• Electrical noise
• Installation problem due to tester

 Figure 2: Single and Multi-junction Thermocouple Sensors [3]

Of the errors listed above, electrical noise is uniquely problematic, especially in today’s high frequency equipment. A TC can be used in a 4-wire format to resolve the electronic noise that may affect the reported temperature. Using a 4-wire thermocouple, as shown in Figure 3, we can measure temperature and electrical noise.

Let us consider a J-type thermocouple formed of Iron and Constantan. All four wires are spot-welded together to form the TC junction. The temperature can be read across any of the Iron and Constantan combinations (?), and the electronic noise can be read across either the two Irons or the two Constantans. Because two similar metals cannot create the Seebeck effect (convert thermal differentials to electric voltage), whatever signal is measured on these wires is the electronic noise in the measurement domain.

 Figure 3: Four-wire Thermocouple System for the Measurement of Electronic Noise and Temperature

Measuring surface temperature is always a challenging process. The following steps will help to increase the accuracy of such measurements:

• Keep installation size as small as possible.
• To reduce conduction errors, bring thermocouple wires away from the              junction, along an isotherm for at least 20 wire diameters.
• Locate the measuring junction as close to the surface as possible.
• To avoid changes in convective or radiative heat transfer, design the installation so that it causes minimum disturbance to any fluid flow or the least possible change in the emissivity of the surface.
• Reduce the thermal resistance between the measuring junction and surface to as low a value as possible.

3 — Diode or Transistor

Diodes and transistors are parts whose electrical properties are a function of temperature. Diodes are broadly used for temperature measurement, either as embedded sensors in functional devices or as a thermal test chips. Figure 4 shows one such thermal test chip for device-level simulation.

Figure 4.  Thermal Test Chip [3]

The following depicts the general considerations for usage of semiconductor materials for temperature measurement:

• Every semiconductor device has at least one electrical parameter that is a              function of temperature.
• Thermal test chips use the thermally sensitive parameter of semiconductor devices to measure chip junction temperature.
• Separate heating and sensing elements are usually used to avoid for electrical switching.
• Thermal calibration of the sensing device is necessary.
• Thermal test chips provide an effective means of measuring chip junction temperature in an actual package configuration.
• Use of materials is subject to availability/suitability for the intended package application.

We’ll conclude our series with part 3, addressing infrared thermography, optical probes and liquid crystal thermography

References:
1. Klinger, D., Nakada, Y., Menendez, M., AT&T Reliability Manual,
Van Nostrand Reinhold, 1990.
2. Azar, K., Thermal Measurement in Electronics Cooling, CRC Press,
1997.
3. Advanced Thermal Solutions, Inc., Tutorial Series, “Principles of
Temperature Measurement”.
4. thermVIEW™ System, product of Advanced Thermal Solutions, Inc.
5. White, F., Viscous Fluid Flow, McGraw-Hill, 3rd Ed., 2005.

If  you are in need of sensors for thermal measurement, click now to ATS’s sensor family.  Tired of using thermocouples that are finicky and breakable? Try ATS’s spot sensor.  It’s durable and cost effective.  Learn more by clicking to ATS Spot Sensor.   You can also email or call us with your questions on temperature measurement and one of our engineers will be happy to help you.  Email us at ats-hq@qats.com or call  us at 781-769-2800.

It is a generally very well attended webinar, covering what new technologies emerged in 2012 in thermal management, which are useful, and which might not be worth checking. To register, click to our GoToMeeting registration page here: Registration for What is The State of the Art in Thermal Management?

In today’s market, it is very rare to see electronic equipment that has not undergone extensive thermal evaluation, either by measurement or simulation. Inevitably, the temperature of the device junction or case, or the enclosure, has been measured to ensure that the system will operate to its intended specifications.  A quick look at the equations associated with stress in a lead wire, and with the acceleration factor used in reliability calculations, will show why temperature plays such an important role in electronics equipment [1].

Equations 1 and 2 clearly demonstrate the linear and exponential relationships that temperature has in the operation of the electronic components. Concurrently, simulation tools are used extensively in today’s thermal design. But, due to the complexity of the electronics packaging and composite nature of the materials used, the simulation data must be verified in order to ensure reliable data is obtained. In this article, we present different sensors and their application domains in electronics thermal management.

Table 1 shows six primary sensors used in temperature measurement:

Table 1.  Standard Temperature Transducers [2]

In part 2 of our three part series, we’ll start consider each sensor in detail, focusing on the resistor thermometer, thermocouple and diode transistor.

References:
1. Klinger, D., Nakada, Y., Menendez, M., AT&T Reliability Manual,
Van Nostrand Reinhold, 1990.
2. Azar, K., Thermal Measurement in Electronics Cooling, CRC Press,
1997.
3. Advanced Thermal Solutions, Inc., Tutorial Series, “Principles of
Temperature Measurement”.
4. thermVIEW™ System, product of Advanced Thermal Solutions, Inc.
5. White, F., Viscous Fluid Flow, McGraw-Hill, 3rd Ed., 2005.

If  you are in need of sensors for thermal measurement, click now to ATS’s sensor family.  Including our industry leading Candlestick Sensor.   You can also email or call us with your questions on temperature measurement and one of our engineers will be happy to help you.  Email us at ats-hq@qats.com or call  us at 781-769-2800.

ATS has expanded once again this week with our tie up with Weiss Company.  Weiss is a Canadian technical electronics sales organization.  We’re excited to have them on board frankly as they bring quite a bit to the Canadian market space.  But, what’s in it for our customers?

First, they are local to Canada.  So while ATS’ main headquarters are in Norwood, MA (just 20 miles south of Boston), we are close to Canada but not in Canada.  Weiss is there and that will make a big difference bringing ATS support to thermal engineers there.

Second, they aren’t “just” a sales organization.  They are composed of both field sales engineers, (FSE) and certified electronics technicians (CET).  What this means for our customers is that Weiss extends ATS’ support network right into Canada.  The Weiss company has a direct like to our factory and design team.  Customers of Weiss/ATS will have best possible support for their thermal management programs.

Third, they have been in the market for 40 years, so they are a stable company with an  understanding of the needs of our customer’s in Canada.

If you are in Canada, drop Ken Kong at Weiss Co an email and let him know ATS sent you, his email is kkong at jgweiss.com

We had a chance to have a quick phone conversation with their Manager of Business Development, Phil Vogel last week.   Test Equipment Connection has been around since 1993.  They both buy and sell test equipment and provide full support.  He noted that thermal analysis and measurement is a growing need in the technology sector and we couldn’t agree more!   Our latest one day short course on thermal management was sold out!

So, if you need test equipment, such as spectrum analyzers or RF or microwave test equipment or ATS thermal test instruments, visit their web site at http://www.testequipmentconnection.com/ and contact them!

You can read more about it at our press release page.