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National Semiconductor’s Three New Boomer Speaker Drivers Enable Thinner, Lighter Handsets with Longer Talk Times

Panasonic Mobile Communications Selects National Technology to Enable Industry’s First Ceramic Speakers in Cell Phones

Jan 6, 2005

January 6, 2005 -  National Semiconductor Corporation (NYSE:NSM) today introduced three Boomer® audio amplifiers, the industry’s first single-chip devices to drive ceramic and piezoelectric speakers in portable applications. These integrated chips allow manufacturers to create “credit-card-thin” handsets or add additional features to designs because they save space and reduce power consumption, enabling longer battery life and talk time.

Ceramic and piezoelectric speakers are dramatically different from conventional moving coil speakers.  They act as a capacitive rather than a resistive load and require much more voltage than current.  In comparison to the 4 mm or greater thickness of traditional moving coil speakers, ceramic speakers are only 0.7 mm thick. They often weigh less than one gram and consume less than 5mW of power.  More information on these speaker types is available in National’s Audio Education Series eBooks at audio.national.com

Japan’s Panasonic Mobile Communications, the first company in the industry to design a ceramic speaker into a cell phone, selected National’s LM4802B and LM4961 speaker drivers for their new line of phones.  In addition to cell phone applications, National’s LM4802B, LM4960 and LM4961 speaker drivers can also be designed into space-constrained portable applications such as personal digital assistants (PDAs), smartphones, notebook computers and other small handheld devices.

"National is continuing to prove its leadership in complete audio solutions,” said Mike Polacek, vice president of National Semiconductor’s Audio Group. "Working closely together with industry leaders Panasonic Mobile Communications and speaker maker Taiyo Yuden in Japan has allowed us to take compelling breakthrough technology for ceramic speakers and bring it to market quickly.  Ultimately, consumers will win when they buy thin Panasonic phones with Taiyo Yuden speakers and National's Boomer audio ICs."

Lighter, Thinner, More Efficient
National Semiconductor’s LM4960, LM4961 and LM4802B single-chip devices integrate a boost converter with an audio power amplifier, replacing the need for expensive voltage regulators and other external components and freeing up space in designs.  The LM4802B and LM4961 audio speaker drivers deliver 12V p/p for ceramic speaker applications and the LM4960 delivers 24V p/p for piezoelectric speakers. 

These amplifiers feature a low-power consumption shutdown mode and an internal thermal shutdown protection mechanism. In addition, they contain advanced “pop and click” circuitry to eliminate noises that typically occur during turn-on and turn-off transitions. All three speaker drivers allow the flexibility of running a handset at a low voltage, increasing talk time in cellular applications.  National’s new amplifiers provide additional benefits such as reduced component count and electromagnetic interference and noise, as well as increased space savings and performance for customers.

The LM4960 is designed for piezoelectric speakers. It integrates a switching regulator, a current-mode boost converter operating at a fixed frequency of 1.6MHz, to drive a dual audio power amplifier. It delivers 24VP-P mono-BTL to a piezoelectric speaker with less than 1% THD+N while operating on a 3V power supply.

The LM4961 for ceramic speakers includes added battery savings, with a low-power mode for earpieces and a high-power mode to drive the ringtones and hands-free speakers. 

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 28-pin pullback LLP® packages, the LM4802B is priced at $1.65 and the LM4961 is priced at $2.10. The LM4960 is available now in a 28-pin non-pullback LLP package and is priced at $2.50.  All pricing is in 1,000-unit quantities.  More information on the LM4802B is available at http://www.national.com/pf/LM/LM4802B.html
, more information on the LM4960 is available at http://www.national.com/pf/LM/LM4960.html.  For an introduction to audio subsystems, visit National’s library of online seminars.  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 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
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