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National Semiconductor Introduces Two Boomer 3D Audio Subsystems with Industry’s Highest Integration for Portable Applications

Jun 14, 2005

June 14, 2005 - National Semiconductor Corporation (NYSE:NSM) today introduced two Boomer® audio amplifiers for cellular phones and portable applications that deliver outstanding sound quality and an unparalleled level of integration in a space-saving package.  These compact audio amplifiers provide ease of use for engineers and great sound for consumers.  National’s LM4845 audio subsystem integrates the audio amplifiers, volume control, mixer, eight output modes, power management control, 3D sound enhancement and I2C compatible control into a single package.  The LM4888 stereo 2.1W speaker and headphone amplifier provides 3D programmability for the speaker and headphone, and ultra-low shutdown current for battery savings.  

"Users of portable devices expect great things from their equipment,” said Mike Polacek, vice president of National Semiconductor’s Audio group.  “As today’s portable devices get smaller and smaller, National’s LM4845 and LM4888 provide the integration that makes it possible to deliver additional features, such as camera phones with audio, MP3 players and FM radios, in a compact package.”

3D Stereo Surround Sound Meets Portable Electronics
National’s LM4845 audio subsystem contains a mono amplifier and stereo headphone amplifier.  The mono amplifier delivers 500mW of power into a mono 8-Ohm bridge-tied load with one percent total harmonic distortion plus noise (THD+N) from a 3.3V power supply. The stereo headphone amplifier delivers 25mW per channel of continuous average power into a stereo 32-Ohm load with one percent THD+N from a 3.3V power supply.  The LM4845 stereo headphone amplifier can be configured for single-ended or output capacitor-less (OCL) operation.  It features a 32-step digital volume control and eight distinct output modes.  The digital volume control, 3D enhancement, and output modes are programmed through a two-wire I2C or three-wire SPI-compatible interface that allows flexibility in routing and mixing audio channels.  This device has three input channels: one pair for a two-channel stereo signal and the third for a single-channel mono input.  It delivers high-quality output power from a surface-mount package and requires only seven external components in the OCL mode and two additional components in the single-ended mode.  Additionally, the LM4845 features a low shutdown current of 0.1uA typical. 

The LM4888 is a dual bridge-connected audio power amplifier which, when connected to a 5V supply, will deliver 2.1W to a 4-Ohm load or 2.4W to a 3-Ohm  load with less than 1.0% THD+N.  A user-selectable 3D enhancement mode provides enhanced stereo imaging. The LM4888 also has two separate headphone enable inputs, each having different logic level thresholds.  Either headphone enable input activates the single-ended headphone mode and disables the bridge-tied load output mode. The headphone sense input is for use with a normal stereo headphone jack.  The remaining input, headphone logic, accepts standard logic level thresholds.  To simplify audio system design, the LM4888 combines dual bridge speaker amplifiers and stereo headphone amplifiers on one chip.  Both the LM4845 and LM4888 feature low-power consumption shutdown modes and thermal shutdown protection and also utilize circuitry to reduce “clicks and pops” during device turn-on.

About National’s Audio Portfolio
National Semiconductor works with every major handset maker in the world and is the leading provider of audio amplifier systems for the cell phone market.  The company’s line of Boomer audio amplifiers enhances and enriches the entire range of sound – from voice, ring sounds and music – that can be amplified in a mobile phone.  National manufactures Class AB and Class D mono and stereo speaker amplifiers, mono and stereo headphone amplifiers, and audio subsystems for desktop and notebook computers, multimedia displays and portable electronic devices.  The company also offers its higher-power Overture® amplifiers for consumer stereo and home theater systems.  For more information on National’s audio products, visit http://audio.national.com

Pricing and Availability
Available now in a 25-bump micro SMD package, the LM4845 is priced at $2.50 and the LM4888 is available in a 25-lead LLP® package and is priced at $1.50, both in 1,000-unit quantities.  Lead-free package options are also available. More information on the LM4845 is available at http://www.national.com/pf/LM/LM4845.html
.  To order a sample of the LM4845, click here.   More information on the LM4888 is available at http://www.national.com/pf/LM/LM4888.html.  To order a sample of the LM4888, click here.   A large selection of audio amplifiers is supported by National’s WEBENCH® online design tool.  To explore these solutions, visit http://webench.national.com.  To learn about high-performance audio amplifiers for portable applications, visit National’s library of online seminars.

Note to editors: To view a high-resolution downloadable photo of the new products, visit National's photo gallery.

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 analog markets include wireless handsets, displays and a variety of broad electronics markets, including medical, automotive, industrial, and test and measurement applications. Headquartered in Santa Clara, California, National reported sales of $1.91 billion for fiscal 2005, which ended May 29, 2005.  Additional company and product information is available at www.national.com