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National Semiconductor Introduces Boomer Stereo Audio Subsystem With 3D Sound

LM4857, National’s Newest Boomer Subsystem, Combines Audio Amplifiers, Volume Control, 16-Mode Mixer and 3D Sound In A Space-Saving Package

Nov 19, 2003

November 19, 2003 - National Semiconductor Corporation (NYSE:NSM), originator of best-in-class Boomer® audio technology, today introduced a Boomer audio subsystem for cell phones that integrates amplifiers, volume and mixing controls and 3D sound in a miniature micro SMD package.

“National Semiconductor’s newest Boomer audio subsystem, coupled with all of National’s market-leading analog technologies for the mobile phone market – our amplifiers, audio, display and power management systems – allows people to change the ways they use their cell phones,” said Ken Boyce, marketing director for National Semiconductor’s audio products group.  “As phones morph into full-featured entertainment devices, cell phone manufacturers demand truer sound, longer battery life, multiple mixing and switching features, and small size.  National’s LM4857 subsystem not only fulfills these specific needs, but also anticipates the feature demands of next-generation handsets.  Our goal is to give designers greater flexibility and give consumers the best audio in the business.”

National’s LM4857 integrates stereo speaker drivers for the handset with 495mW output power per channel, a 33mW stereo headphone driver with 32-step volume control and independent left, right and mono volume controls.  Operating on a 3.3V supply, it combines a stereo speaker amplifier for improved sound quality over single mono speakers, a mono earpiece amplifier that delivers 43mW into a 32W load, and a line output for an externally powered hands-free speaker (such as a car kit).

The LM4857’s 3D enhancement improves stereo channel separation when the left and right speakers are too close together and solves problems that would otherwise arise from system size constraints or equipment limitations.  In addition, the LM4857 routes and mixes the stereo and mono inputs into 16 distinct output modes that give designers flexibility to route and mix mono and stereo audio signals without limiting routing just to stereo speakers or stereo headphones.  The LM4857 is controlled through an I2C compatible interface.

About National’s Audio Portfolio
Working with every major handset maker in the world, National Semiconductor is the leading provider of audio amplifier systems for the cell phone market.  The company’s line of Boomer audio amplifier products enhance and enrich the entire range of sound – from voice, ring sounds and music – that can be amplified in a mobile phone.  National also manufactures class AB and Class mono, stereo, and headphone audio amplifiers and audio subsystems for desktop and notebook computers, displays, consumer and other portable electronic devices, as well as consumer stereo and home theater systems.  For more information on National’s audio products, visit http://www.national.com/appinfo/audio/

Pricing and Availability
The LM4857 is available now in 30-bump micro SMD packaging and is priced at $2.70 in 1,000-unit quantities.  More information on the LM4857 is available at http://www.national.com/pf/LM/LM4857.html
.  To view a high-resolution downloadable photo of the LM4857, visit National's photo gallery at http://www.national.com/company/pressroom/gallery/audio.html.

About National Semiconductor
National Semiconductor is the premier analog company. Combining real-world analog and state-of-the-art digital technology, the company is focused on analog-based semiconductor products, which include stand-alone devices and subsystems in the areas of power management, display drivers, audio, amplifiers, imaging and data conversion. The company targets key markets such as wireless, displays, PCs, networks and a broad range of portable applications. With headquarters in Santa Clara, California, National reported sales of $1.67 billion for fiscal 2003, which ended May 25, 2003. Additional company and product information is available on the World Wide Web at www.national.com