With telecom and distributed-power applications leading the charge, the surface-mount dc/dc converter industry is poised to jump to power levels unheard of only two years ago. After reaching the 50-watt level this year from the previous 20 to 25 W, converter makers say a 100-W device in a superlight package for today's pick-and-place equipment will be here before the end of next year.
"We see the higher-powered converters as a natural migration for surface mounting," said Barry Papermaster, director of marketing for power systems at Lucent Technologies (Mesquite, Texas). "There was barely a market for us in surface-mount converters just a short time ago," he continued. "By 2003, that could be a quarter of our dc/dc converter business."
Progress in 1999 took a big leap thanks to a variety of evolving design and packaging technologies. These included advances in lightweight materials, planar magnetics and circuit design first evident in Lucent's Titania nonisolated, through-hole modules two years ago, as well as seen in regulators from TI Power Trends (Warrenville, Ill.).
The first announced module in the 25-W-and-above area specifically for surface mounting and having a flat, rectangular construction meeting the typical user's expectation came from Lambda (Melville, N.Y.). The 20-member SM 30-W convection-cooled series for telecommunications had single, dual and triple outputs (see photo, page 83).
Key to this module, as to many others, are thermal-management strategies that have eliminated the case-sealing potting material in order to cut size and weight, in this case down to 2.5 x 2.5 x 0.4 inches and 38 grams.
The Lambda device also uses a special pc-board material for handling heat dissipation that has 10 times the thermal-transfer capabilities of an FR-4 substrate. The Lambda family may reach 100 W by the end of next year.
TI Power Trends introduced its 30-W PT3320/ PT3340 converters earlier than the Lambda series, although the open-frame 19-pin SIP devices were not touted for surface mount-ing. They are, however, fully compatible with existing pick-and-place equipment, according to the company.
Intended for integration in 48-V distributed-power applications, these single-output converters, with an efficiency of 85 percent, deliver from 2- to 15-V output. The converters weigh about 40 grams.
Acute Power (Attleboro, Mass.) then introduced its 12-model SLV40 series of synchronous low-voltage, single-output converters (also available is the MAC30, a 30-W isolated triple-output converter).
The series has a unique thermal configuration, flexible heat-sinking arrangement and package size appropriate to the application rather than a sizing standard, said Bill King, the company's founder and president.
Also important was its weight for pick-and-place equipment. "Getting around the potting problem was key for us," said King. "We went to a bonded metal substrate to cut the weight and achieve the tight seal needed as well."
These 12-, 24- and 48-V input models (the latter two providing a maximum rated power of 40 W continuous) feature the integral metal substrate for unique thermal management and open-frame construction in a synchronous-rectifier topology that provides efficiencies from 81 to 90 percent.
The converter measures 1.75 x 2 x 0.5 inches and weighs 28 grams.
Lucent's JAHW/JAHC, announced in October, established yet another high in surface-mount power capability to 50 W continuous. Key to the development of these half-brick (2.4 x 2.28 x 0.5-inch) units, which weigh 37 grams, was a ball-grid design. "The breakthrough for us was the ball-mount design, which we found more compliant than the solder joint," said Lucent's Papermaster. "It largely enables us to extend the technology to higher powers."
Presently, the industry sees steady growth both in terms of volume demand and power capacity. Forty- and 50-W devices could well become industry-standard during the next year.
"We're working in the 80-W area right now," said King of Acute Power. "We see a 100-W device in the near future." Lucent's Papermaster echoed that sentiment.
"Right now, nothing in the technology seems to stand in the way of our developing 75- and 100-W devices by the end of 2000. And so we'll see if we can do it," he said.
TI Power Trends
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Acute Power Inc.
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