March 25, 2002-National Semiconductor Corporation (NYSE:NSM), providing best-in-class technology, packaging and performance for next-generation audio products, today announced two BoomerŪ stereo headphone amplifiers with space-saving features that make them ideally-suited for headphone applications in small, portable devices such as mobile phones, PDAs, MP3 players and other portable electronic equipment.
"National Semiconductor is continuing to expand the Boomer portfolio with two new market leaders, " said Hector Hernandez, marketing manager for National Semiconductor's audio products group. "The LM4910 and LM4911 feature the Boomer family's revolutionary output capacitor-less (OCL) headphone design, which eliminates two output coupling capacitors that are needed in all headphone applications. The LM4910 is the market's first 5V headphone amplifier capable of eliminating output coupling capacitors, affording the customer substantial savings in board space and manufacturing time. The LM4911 is the industry's first 5V headphone amplifier with selectable OCL mode or capacitive coupled mode available in 8-pin MSOP packaging. These features provide flexibility in design with minimal board space requirements."
LM4910
The LM4910 is an audio power amplifier primarily designed for headphone applications in portable devices. It is capable of delivering 35mW of continuous average power to a 32 ohm BTL load with less than 1% distortion (THD+N) from a 3.3V DC power supply. National's LM4910 utilizes a new circuit topology that eliminates output coupling capacitors and half-supply bypass capacitors. This device contains advanced pop and click circuitry, which eliminates noises caused by transients that would otherwise occur during turn-on and turn-off.
The LM4910 provides high-quality output power with a minimal amount of external components. Because it does not require any output coupling capacitors, half-supply bypass capacitors, or bootstrap capacitors, it is ideally suited for low-power portable applications where minimal space and power consumption are primary requirements. Additionally, the LM4910 features a low power consumption shutdown mode, activated by driving the shutdown pin with logic low. The LM4910 also features an internal thermal shutdown protection mechanism and is unity-gain stable. It can be configured using external gain-setting resistors.
LM4911
The LM4911 features a low-power consumption shutdown mode and a power mute mode that allow for faster turn-on time with less than 1 mV voltage change at outputs on release. It is capable of delivering 40mW per channel of continuous average power into a 16 ohm load, or 25mW per channel into a 32 ohm load at 1% THD from a 3V power supply. Additionally, the LM4911 has an internal thermal shutdown protection mechanism. This device is unity-gain stable and may be configured with external gain-setting resistors.
Pricing and Availability
The LM4910 is available now in 8-pin SOIC and MSOP packaging and is priced at $0.75. The LM4911 is available in 10-pin MSOP packaging and is priced at $0.75. Both product prices are for 1,000-unit quantities. More information on these products is available at http://www.national.com/pf/LM/LM4910 and http://www.national.com/pf/LM/LM4911. For more information on National's audio products, visit http://www.national.com/appinfo/audio/. To view a high-resolution downloadable photo of these products, 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 the fast growing markets for wireless handsets; displays; information appliances; and information infrastructure. With headquarters in Santa Clara, California, National reported sales of $2.1 billion for its last fiscal year and has about 9,800 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com.
