August 20, 2001 - National Semiconductor Corporation (NYSE:NSM) today announced the LM4894 and LM4895 BoomerŪ audio amplifiers that are optimized for the cellular phone market, delivering the best possible PSRR performance available in the industry. Improved PSRR performance reduces the effect of noise on power supply lines being picked up and intensified by the audio amplifier. As a result, there is less noise to the earpiece speaker in cellular phone applications. Higher PSRR also eliminates the need for additional components to condition the power supply lines. The LM4894 and LM4895 are designed for use in cellular phones, PDAs and other portable electronic devices.
"National has the number one market share in audio amplifiers for the cellular market," said Hector Hernandez, marketing manager for National's audio amplifier product line. "These new Boomer amplifiers will enable our customers to make cellular phones with sharper, clearer audio quality. The fully-differential design of the LM4894 and LM4895 allows them to deliver the best possible PSRR performance available in an audio amplifier for the cellular market."
With the input terminated with a 10 ohm resistive load, the LM4894/95 deliver 80dB PSRR at 217Hz at 3V. With the input un-terminated (floating), the LM4894/95 deliver 87dB PSRR at 217Hz at 3V. They also deliver 50dB of CMRR (common mode rejection ratio), a specification not possible in typical BTL configuration amplifiers. An additional feature of the LM4894 and LM4895 is the selectable shutdown mode. This allows designers to select either shutdown logic high or shutdown logic low. The LM4894/95 have been optimized to save power by operating at a low supply voltage (3V), while still providing sufficient output power (350mW, 8 ohms, <1%THD), suitable for normal listening and speakerphone and ringer tone amplification.
LM4894
Because of the fully-differential design of the LM4894, the input coupling capacitor is eliminated, thereby reducing pop and click noise at turn-on and turn-off. This device also offers an external gain configuration capability and has an internal thermal shutdown protection mechanism.
LM4895
The LM4895's fully-differential design and 6 dB fixed gain bring the simplest audio amplifier solution available in the market. This device eliminates all of the external components required, except for one external capacitor, saving the customer design and manufacturing time, board space, component count, and costs.
Pricing and Availability
The LM4894 and LM4895 are available now in 9-bump micro SMD, 10-pin LLP and 10-pin MSOP packaging. The LM4894 is priced at $0.80, and the LM4895 is priced at $0.83, both in 1,000-unit quantities. More information on these products is available at http://www.national.com/pf/LM/LM4894.html and http://www.national.com/pf/LM/LM4895.html. For more information on National Semiconductor's audio products, visit http://www.national.com/appinfo/audio/. To view a high-resolution downloadable photo of the LM4894 and LM4895 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; information appliances; information infrastructure; and display, imaging and human interface technologies. With headquarters in Santa Clara, California, National reported sales of $2.1 billion for fiscal year 2001 and employs about 9,700 people worldwide. Additional company and product information is available on the World Wide Web at www.national.com.
