Electronic Design

Cooling Devices

Interface Technology Solders Power Packages Directly Onto Heatsinks
The PowerSite thermal interface technology creates low-thermal-impedance, electrically isolated interface locations. It allows power packages to be directly soldered onto heatsinks.

This automated process selectively bonds 1-oz. copper patches to aluminum heatsinks in the spaces where power devices are to be mounted. Since no etching processes are required, PowerSite patches can be applied to heat-sinks of any size or shape. In the final step, the process solders devices in place. This process eliminates the need for hardware, mounting holes, and insulator pads. It also eliminates pressure dependency.

This process achieves thermal impedance as low as 0.1°C-in.2/W. The high-temperature, all-polyimide insulation with conductive Kapton MT enables a dielectric strength of greater than 4000 V and a voltage breakdown of 5000 V ac. It accommodates many standard solderable packages, including TO-220, TO-247, and TO-218. According to the company, the technology achieves a higher degree of design flexibility. Designers can reduce power-device temperatures or heatsink size. Optionally, designers can increase ambient temperature or power rating.

For pricing and availability information, contact the company.

Chomerics, 77 Dragon Ct., Woburn, MA 01888-4014; (781) 935-4850; fax (781) 933-4318; www.chomerics.com.

Thermal Diode Monitor Features High-Accuracy Sensing
The ADM1032 is a high-accuracy remote thermal diode monitor available in an 8-pin µSOIC package. Its small size suits it for portable and space-constrained applications, such as thin-and-light notebook computers. Additional features suit this monitor for applications requiring a thermal management system, including desktop computers, set-top boxes, industrial controllers, instrumentation, and telecom equipment.

This device has a high accuracy rating of ±1°C. This allows system designers to reduce temperature guardbanding safely and increase system performance because of minimal clock throttling. Under- and overtemperature limits can be programmed into a particular device over the standard system management bus (SMBus), with an alert output signaling when an on-chip or remote temperature measurement is out of range. This programmable capability gives OEMs the flexibility to use only one IC instead of multiple platforms that may require different thermal settings.

The ADM1032 enables 0.125°C-resolution/1°C accuracy on the remote channel. Operating from a 3- to 5.5-V supply, this device has a 160-µA maximum operating current and a 3-µA standby current.

This device is available in µSOIC and SOIC packages. In 1000-unit quantities, the ADM1032 costs $1.99 each. OEM discounts for large quantities bring the cost down to $1.00 each.

Analog Devices, One Technology Way., P.O. Box 9106; Norwood, MA 02062-9106; (781) 329-4700; fax (781) 329-8703; www.analog.com.

Series Of CPU Coolers Suits High-Power Chips
Members of a CPU cooler series are suited for use with high-power chips. The four available models are designed to cool Pentium III and Athlon chips up to 1 GHz. These devices also cool other CPUs, including the Celeron and the AMD K6.

Complete with the company's patented Vapo bearing system, these coolers feature an input voltage of up to 12 V dc. Air delivery is rated at up to 16 CFM. Available speeds are 5500 and 6500 rpm. All models feature a thermal impedance of 0.03°C-in.2/W. The 53- by 50- by 42-mm and 53- by 50- by 47-mm package CPU coolers suit the Socket 370 CPU. While the 124- by 53- by 47-mm package suits the Athlon CPU, the 137- by 47- by 45-mm cooler suits the Pentium III SECC2 CPU. Contact the company for pricing and availability information.

Sunon Inc., 1075-A W. Lambert Rd., Ste. A, Brea, CA 92821; (714) 255-0208; fax (714) 255-0802; www.sunon.com.

Fans Provide Thermal Management For A Variety Of Applications
Members of the OptiFan line of dc fans meet thermal-management needs for a range of applications, from small personal computers and electronic enclosures to telecom and industrial equipment.

According to the company, these fans are designed to meet customers' needs in an ever-changing thermal environment. They have been extensively tested and verified. A quieter fan is ensured through design refinements in the fan blade and housing. The noise emitted from the fan bearings has also been minimized by proper bearing selection and mounting techniques. Some of the OptiFan devices provide optional internal speed control that varies fan airflow based on the temperature of the ambient air. This internal thermistor-controlled circuitry responds to a change in air temperature by varying motor speed. This option can be used to reduce airflow, acoustic noise, and power consumption when high airflow is not needed.

The 40- by 40- by 7-mm fan has an airflow delivery rate of 3 CFM. The 120- by 120- by 38-mm fan has an airflow delivery rate of 100 CFM. Prices range from $2 to $5, depending on bearing style, motor speed, and other options.

Aavid Thermalloy, 80 Commercial St., Concord, NH 03301; (603) 223-9988; fax (603) 223-1790; www.aavidthermalloy.com.

Thermally Conductive Silicone Adhesive Offers High Bond Strength
The 5405 adhesive is ideal for bonding heat-generating power devices to heatsinks. This thermally conductive silicone adhesive offers low thermal resistance and high bond strength.

This adhesive is a single-component, zinc-oxide filled, heat-curable silicone that cures to a flexible, electrically isolating material. Capable of producing a very thin bond line, this adhesive can be used to bond the die to the lid in applications requiring compliant materials that do not induce stress. It is designed to bond metallic heat sinks, ceramic chips, and circuit board substrates. The 5405 cures in just 10 minutes when exposed to a temperature of 150°C.

For information concerning pricing and availability, contact the company.

Loctite Corp., 1001 Trout Brook Crossing, Rocky Hill, CT 06067; (800) LOCTITE; fax (860) 571-5465; www.loctite.com.

Mini Cabinet Cooler Maintains 60-dBA Sound Levels At 3 Ft.
The mini Cabinet Cooler protects electronics from high external temperatures while maintaining sound levels of only 60 dBA at 3 ft. This compact air conditioner now features internal muffling for quiet operation and an external sleeve for added insulation.

The device's 5.2-in. height makes it ideal for confined spaces. It has a vortex that tube cools ordinary compressed air to 20°F. The cool air is then circulated through the enclosure to eliminate high-temperature malfunctions. This also provides a constant purge to keep the panel free of dust and contaminants. Systems include thermostat control to minimize air usage as well as a compressed air filter to ensure the air is clean and dry.

This unit installs quickly through a standard electrical knockout. It will maintain the NEMA 12 integrity of the enclosure. It boasts a 550 Btu/hr cooling capacity for moderate heat loads. Other NEMA 12, 4, and 4X (stainless steel) models are available with capacities up to 2800 Btu/hr. According to the company, this device cools such applications as programmable controllers, CNC panels, camera and laser housings, and computer cabinets. For pricing and availability information, contact the company.

Exair Corp., 1250 Century Circle N., Cincinnati, OH 45246-3309; (800) 903-9247; fax (513) 671-3363; www.exair.com.

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