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National Semiconductor’s 34V High-Fidelity Audio Op Amp Drops Distortion Rate to 0.00003 Percent

LM4562 Sets New Level of Performance For High-End Professional Audio Applications

Sep 25, 2006

September 25, 2006 - A new dual, high-fidelity audio operational amplifier from National Semiconductor Corporation (NYSE:NSM) practically eliminates distortion, with total harmonic distortion plus noise (THD+N) of 0.00003 percent.  The LM4562 amplifier joins the recently introduced LM4702 high-voltage stereo driver as a member of National’s new high-performance audio family.

National’s LM4562 sets a new level of performance with its remarkably low distortion, low noise, high speed, wide operating voltage and high output drive. These features make the op amp well-suited for professional and high-end audio applications such as audio/visual (AV) receivers, preamplifiers and mixers, as well as a range of 34V medical imaging and industrial applications.

The LM4562 offers all the key specifications needed for superior audio performance and signal conditioning. The op amp features low-input noise density of 2.7 nV/sqrt Hz, a 1/f noise corner of 60 Hz and 600-Ohm output drive. To ensure that the most challenging high loads are driven without any noise compromise, the LM4562 has a slew rate of 20 V/us and a 56 MHz gain bandwidth.  The dual op amp is available in 8-lead SOIC, dual in-line (DIP) and metal can packages.  Single and quad versions of the op amp will be available in early 2007.

Key Technical Features and Benefits
The LM4562 is unity-gain stable over a wide supply range of plus or minus 2.5V to 17V and has output current capability of 45 mA. Over this supply range, the LM4562’s input circuitry maintains common-mode and power-supply rejection rates (PSRR) of more than 108 db and a typical low input bias current of 10 nA. The op amp offers a full audio dynamic range maximized with an output stage. This output stage can swing to within 1V of either power supply voltage when driving 2-kiloOhm loads or to within 1.5V when driving 600-Ohm loads.

The op amp retains its performance levels while driving capacitive loads as high as 100 pF. It also features thermal shutdown and output short-circuit protection.

Pricing and Availability
Available now, the LM4562’s standard SOIC package is priced at $2.35 each and the DIP package is priced at $2.65 each in 1,000-unit quantities. The metal can package is priced at $9.95 each in 100-unit quantities.  Lead-free package options that are compliant with the European Restriction on the use of Certain Hazardous Substances (RoHS) directive are also available. More information, easy-to-order samples and evaluation boards are available at http://www.national.com/pf/LM/LM4562.html.

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

About National’s Audio Portfolio
National Semiconductor has been a leading provider of audio solutions for more than 30 years and offers a wide range of products in its Boomer®, Overture® and high-performance audio lines. National works with every major handset maker in the world and is the leading provider of analog audio solutions for the cell phone market. The company's line of Boomer audio amplifiers and subsystems enhance and enrich the entire range of sound – from voice, ring sounds and music – that can be amplified in mobile phones and other portable equipment.  National manufactures Class AB and Class D speaker amplifiers, headphone amplifiers and audio subsystems for many applications ranging from portable devices to high-power, high-fidelity audio systems. The company offers its higher-power Overture amplifiers for mid-performance consumer applications, and National’s new high-performance series brings dramatically improved sound quality to high-fidelity consumer and professional audio equipment. For more information on National’s audio products, visit http://audio.national.com.

About National Semiconductor
National Semiconductor, the industry's premier analog company, creates high-value analog devices and subsystems.  National's leading-edge products include power management circuits, display drivers, audio and operational amplifiers, 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, Calif., National reported sales of $2.16 billion for fiscal 2006, which ended May 28, 2006.  Additional company and product information is available at www.national.com.