National Semiconductor’s Newest Boomer Multimedia Audio System Integrates Tone and Volume Control, Microphone Preamp, Headphone Driver and 3D Sound

June 5, 1997 -- National Semiconductor Corporation® today raised the level of integration for audio amplifiers to meet the company’s system-on-a-chip strategy. The newest member of its high-efficiency, low-voltage Boomer audio amplifier IC family is specifically designed for multimedia video monitors requiring audio capability for applications such as video conferencing, game playing, and movie or audio editing.

“The LM4832 is truly the first of its kind,” said Todd Moore, National’s strategic audio marketing engineer. “With this single device, designers can add full user controllability of treble, bass, volume, 3D sound and microphone sensitivity, as well as stereo audio amplification into speakers or headphones. It’s made-to-order for anyone designing multimedia products with quality audio reproduction from video monitors, notebook and desktop PCs, portable TVs and portable CD players.” National’s LM4832 facilitates front panel push-button adjustment of key audio functions through a simple I2C serial interface. A two-input microphone preamp with adjustable gain gives the user control of both microphone type and attenuation level. National’s proprietary, royalty-free 3D-sound enhancement circuitry is also externally adjustable with a simple RC network.

Several features of the LM4832 make it highly desirable for use in multimedia applications:
The LM4832’s headphone drivers typically deliver 200mW at 5V into an 8-ohm load with less than 10% THD and 75mW into a 32-ohm load.

The LM4832 can also control an external audio power amp through its own I2C interface and a logic level control pin.

An independent mute for power and microphone amplifiers maximizes system flexibility and performance.

A power-saving shutdown/mute mode extends operating time of battery-powered systems.

An internal thermal shutdown mechanism protects the device from overheating, making the LM4832 virtually indestructible. It also operates without the aid of bootstrap capacitors or snubber networks. A minimal number of external components, combined with the product's 28-pin footprint, greatly simplifies overall system design, saves board space and lowers manufacturing costs.

Price and Availability
The LM4832 is currently available in either a 28-pin DIP (LM4832N) or LM4832M surface-mount package (SOIC). In quantities of 1000, it is priced at $2.99 in either package.

For more information on the LM4832, please visit our World Wide Web site at http://www.national.com/pf/LM/LM4832.html.

National Semiconductor Corporation, a Fortune 500 Company, produces system-on-a-chip silicon solutions for the information highway, based on its leadership in analog and mixed signal technologies. National is headquartered in Santa Clara, California, and focuses on the communications, personal systems and consumer markets. In March 1997 National sold its Fairchild Semiconductor businesses and now has 12,300 employees worldwide with annual sales of approximately $2.0 billion. Additional company and product information is available on the World Wide Web at www.national.com.

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