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National Semiconductor Introduces Industry’s First Audio Amplifier That Eliminates Bypass Capacitor

Streamlined Architecture of National’s LM4906 Reduces Component Count, Saving Board Space and Manufacturing Time for Customers

Aug 18, 2003

August 18, 2003 - National Semiconductor Corporation (NYSE:NSM), providing best-in-class technology for analog products, today announced a Boomer® audio amplifier that eliminates the bypass capacitor typically connected to the reference voltage pin.  National’s new architecture improves power supply rejection ratio (PSRR) and provides very fast turn-on times. These features are ideal for applications in small, portable devices such as mobile phones and notebook computers.

“National Semiconductor is continuing to expand its Boomer amplifier portfolio with a product that sets the pace for the audio amplifier market,” said Ken Boyce, marketing director for National Semiconductor’s audio products group.  “National’s LM4906 features patent-pending architecture that eliminates the need for the reference voltage bypass capacitor, thereby reducing system cost, saving board space and manufacturing time for customers.  The product’s fast turn-on and turn-off times are also very important for power consumption, enabling aggressive power management and longer talk time in cellular applications.”

Designed to improve overall system performance, the LM4906 was created for demanding applications in mobile phones and other portable communication devices.  It is capable of delivering 1W of continuous average power to an 8 Ohm bridge-tied load (BTL) with less than 1% total harmonic distortion plus noise (THD+N) from a 5V DC power supply.  The LM4906 has an internal selectable gain of either 6dB or 12dB.  It does not require output coupling capacitors or bootstrap capacitors. 

The LM4906 contains advanced pop and click circuitry that eliminates noise which would otherwise occur during turn-on and turn-off transitions.  Additionally, the LM4906 features a low power consumption shutdown mode (the part is enabled by pulling the shutdown pin high) and an internal thermal shutdown protection mechanism.

About National’s Audio Portfolio
With a dominant market share in audio amplifiers in cellular handsets, National supplies nearly every handset maker in the world.  In addition to providing chips for cellular handsets, National manufactures Class AB and Class D audio amplifiers for consumer stereo and home theater systems, and headphone and speaker drivers in notebook computers and portable audio devices.   For more information on National’s audio products, visit http://www.national.com/appinfo/audio/

Pricing and Availability
The LM4906 is available now in LLP® chip-scale packaging and MINI SOIC packaging and is priced at $0.60 in 1,000-unit quantities.  More information on the LM4906 is available at http://www.national.com/pf/LM/LM4906.html
.  To view a high-resolution downloadable photo of the LM4906, 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 driving the information age. 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, imaging, display drivers, audio, amplifiers 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 its most recent fiscal year. Additional company and product information is available on the World Wide Web at www.national.com