National Semiconductor’s Third Generation Simple Switcher® DC/DC Converters Operate at >90% Efficiency in an SO-8 Package

June 19, 1997 -- National Semiconductor Corporation® today announced availability of the first in a series of high-efficiency Simple Switcher® step-down power converters. The new devices feature efficiency ratings greater than 90%, making them ideal for battery-powered designs where cool operation, long life and small size are required.

The two new parts - LM2672 and LM2675 - are rated at 1A output, with only PCB traces used as a heat sink. In addition, the higher frequency of the switchers - 260KHz - allows designers to build a power supply with just five low-profile surface-mount components. Voltage options include 3.3V, 5V 12V and adjustable.

"Higher efficiency means less power dissipation, allowing a smaller form factor," said Barry Signoretti, National's analog product marketing manager. “The unique, easy-to-use Simple Switcher concept now offers a choice for designers of battery-powered applications with limited space requirements and low heat tolerance."

National Guarantees Switchers-Made-Simple Circuit Performance Popular circuit-design features of National's original line of Simple Switchers include new Windows-compatible Switchers-Made-Simple design software, version 5.0. The new software provides customers with a complete design solution including schematics, component lists and vendor information. Use of standard inductors or transformers available from National's magnetics partners precludes the need for any magnetics design. National guarantees system performance for DC/DC converter applications designed using the components listed in either the company's design software or data sheets.

The LM2672 also features frequency synchronization that helps reduce system noise and EMI. A soft-start feature prevents excessive in-rush current and reduces transient voltage surges. Both new ICs offer external shutdown and self-protection features such as current limiting and over-temperature shutdown.

The LM2672 and LM2675 are available in the popular SO-8 package or 8-lead DIPs. Proven design of the devices offers the same ease of use that has made Simple Switcher ICs the most widely accepted category of DC/DC converters available.

Price & Availability

High-efficiency Simple Switcher Converters are available in either an 8-lead DIP or the SO-8 surface mount packages. Pricing in 1000-lot units for the LM2672 is $3.45 for the N-Version (DIP package) and $3.68 for the M-Version (SO Package). The LM2675 is priced at $3.22 and $3.45 for the N- and M-versions, respectively.

For more information on the LM2672 or LM2675, visit our website at http://www.national.com/pf/LM/LM2672 html or http://www.national.com/pf/LM/LM2675.html.

National Semiconductor Corporation, a Fortune 500 Company, produces system-on-a-chip silicon solutions for the information highway, based on its leadership in analog and mixed signal technologies. National is headquartered in Santa Clara, California, and focuses on the communications, personal systems and consumer markets. In March 1997, National sold its Fairchild Semiconductor businesses and now has 12,300 employees worldwide with annual sales of approximately $2.0 billion. Additional company and product information is available on the World Wide Web at www.national.com.