Product category: Analogue and Mixed Signal ICs
News Release from: National Semiconductor | Subject: LM4857
Edited by the Electronicstalk Editorial Team on 25 November 2003
Cellphone stereo audio shrinks to tiny
package
A new Boomer audio subsystem for cellphones integrates amplifiers, volume and mixing controls and 3D sound into a single miniature micro SMD package.
A new Boomer audio subsystem for cellphones integrates amplifiers, volume and mixing controls and 3D sound into a single miniature micro SMD package "National Semiconductor's newest Boomer audio subsystem, coupled with all of National's market-leading analogue technologies for the mobile phone market - our amplifiers, audio, display and power management systems - allows people to change the ways they use their cellphones", said Ken Boyce, Marketing Director for National Semiconductor's Audio Products Group
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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"As phones morph into full-featured entertainment devices, cellphone manufacturers demand truer sound, longer battery life, multiple mixing and switching features, and small size.
National's LM4857 subsystem not only fulfils these specific needs, but also anticipates the feature demands of next-generation handsets.
Our goal is to give designers greater flexibility and give consumers the best audio in the business".
National's LM4857 integrates stereo speaker drivers for the handset with 495mW output power per channel, a 33mW stereo headphone driver with 32-step volume control and independent left, right and mono volume controls.
Operating on a 3.3V supply, it combines a stereo speaker amplifier for improved sound quality over single mono speakers, a mono earpiece amplifier that delivers 43mW into a 32ohm load, and a line output for an externally powered hands-free speaker (such as a car kit).
The LM4857's 3D enhancement improves stereo channel separation when the left and right speakers are too close together and solves problems that would otherwise arise from system size constraints or equipment limitations.
In addition, the LM4857 routes and mixes the stereo and mono inputs into 16 distinct output modes that give designers flexibility to route and mix mono and stereo audio signals without limiting routing just to stereo speakers or stereo headphones.
The LM4857 is controlled through an I2C compatible interface.
The LM4857 is available now 30-bump micro SMD packaging and is priced at $2.70 in 1000-unit quantities.
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