Low distortion audio/data switches for portable applications

26th April 2006

ES Admin

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Intersil’s ISL54400, ISL54401 and ISL54402 are said to be the first commercially available audio/data switches in the industry to provide both low-distortion audio and USB switching capabilities. Combining data and audio switches eliminates either the USB or headphone connector in devices such as portable MP3 players and camera phones, providing cost savings. Also, automatic USB cable detection and the integration of external components associated with the USB data rate negotiation function results in further cost and space savings.

The devices combine high bandwidth, low-capacitance switches for data signals, with very low distortion, low-capacitance switches for audio, so they can be used alternately for USB full-speed data download and 20mW per channel of MP3 encoded stereo audio playback through the same device.
The ISL54400/01/02 improve audio playback quality, eliminate external components and save significant board space over competing solutions. The devices are designed for mixed audio and data switching in handheld and audio accessory applications.

The ISL54400 is a full-function device that has audio switches that provide a very low-distortion path suitable for MP3 playback into stereo headphone loads and can handle negative signal swings up to 20mW power levels into a 32 Ohm headphone load without clipping. It includes USB cable detection and data rate negotiation hardware functions. The ISL54401 includes the USB cable detection but not the data rate negotiation hardware functions. The ISL54400 provides none of the USB functions and is a basic audio/data switch.

Target applications for the devices are MP3 and other personal media players, cellular/mobile phones, PDAs, USB switching and audio/USB switching. The devices are available now in 10-lead TDFN packaging and ultra-thin micro QFN, which saves 67 percent board area compared to a traditional TDFN package.