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National Semiconductor Introduces Two High Efficiency Class D Boomer Audio Amplifiers for Cellular Phones and Flat Panel Monitors

Sep 13, 2004

September 13, 2004—National Semiconductor Corporation (NYSE:NSM), originator of best-in-class Boomer® audio technology, today expanded its audio Class D portfolio with two high efficiency Boomer audio amplifiers.  National’s LM4666 is a stereo speaker amplifier with selectable gain to give customers flexibility and ease of use in cellular phones and other portable handheld devices.  The LM4668 is a switching power amplifier designed for demanding applications in flat panel monitors and televisions and computer sound cards.

“The LM4666 and LM4668 Class D amplifiers address two very distinct needs for our customers,” said Gary Adrig, marketing director for National Semiconductor’s audio products group.  “Manufacturers of flat panel monitors and TVs demand superior audio performance and efficiency.  The LM4668 has soft-start circuitry to eliminate noise during turn-on transitions and fixed, internally set gain for customers’ ease of use.  Handset makers will prefer the LM4666, which offers higher efficiency for reduced overall system heat and longer battery life – essential for products with small board areas that are extremely sensitive to heat dissipation.”  

Superior Sound
National’s LM4666 is a 1.3-watt-per-channel, high efficiency, fully differential Class D stereo speaker amplifier with selectable gain of 6-12dB.  In addition to flexibility and ease of use, selectable gain in this one-chip stereo solution reduces overall system cost by minimizing component costs and board space.  The high efficiency of this part reduces power consumption and minimizes heat dissipation from the amplifier within the system, leading to extended battery life and increased talk time in cellular applications.  Additionally, the LM4666’s delta-sigma modulation technique lowers output noise and total harmonic distortion (THD) when compared to conventional pulse width modulation (PWM) Class D amplifiers.

The LM4668 is a 10-watt high efficiency mono audio power amplifier with a gain of 30dB.  It provides 10 watts of power into an 8-ohm load at 10 percent total harmonic distortion plus noise (THD+N) from a 14-volt power supply.  Because of this part’s high efficiency, it reduces overall heat dissipation, making the customers’ applications more reliable. The LM4668 also uses a unique balanced PWM that makes it more immune to noise for a quieter user experience. This device is ideal for flat panel displays, such as PC monitors and TVs, as these applications require small IC footprints and low heat dissipation.

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 D 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.audio.national.com
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Pricing and Availability
The LM4666 is available now in 14-lead LLP® packaging and is priced at $0.90.  The LM4668 is available now in 14-lead LLP packaging priced at $1.58, and 20-lead TSSOP packaging priced at $1.58.  All prices are for 1,000-unit quantities.  More information on the LM4666 is available at http://www.national.com/pf/LM/LM4666.html
, and more information on the LM4668 is available at http://www.national.com/pf/LM/LM4668.html .  To view a high-resolution downloadable photo of the LM4666 and LM4668, visit National's photo gallery at http://www.national.com/company/pressroom/gallery/audio.html.

About National Semiconductor
National Semiconductor, the industry's premier analog company, creates high performance analog devices and subsystems.  National's leading-edge products include power management circuits, display drivers, audio and operational amplifiers, communication interface products and data conversion solutions. National's key markets include wireless handsets, displays, PCs and laptops.  The company's analog products are also optimized for numerous applications in a variety of electronics markets, including medical, automotive, industrial, and test and measurement.  Headquartered in Santa Clara, California, National reported sales of $1.98 billion for fiscal 2004, which ended May 30, 2004.  Additional company and product information is available at www.national.com.