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Audio processor eliminates need for external MCU

Posted: 01 Jun 2006 ?? ?Print Version ?Bookmark and Share

Keywords:Maxim? MAX5406? audio processor?

MAX5406 audio processor

Maxim Integrated Products has introduced the MAX5406, an audio processor that promises a simple, debounced pushbutton interface.

Maxim said the device integrates all the op amps and potentiometers necessary for implementing and controlling standard audio functions: balance, volume, tone, treble, bass, bass boost and ambience. For ultimate design flexibility and space savings, said the company, device eliminates the need for an external microcontroller (MCU) to control functions or respond to the pushbuttons.

The audio processor accommodates the new multimedia applications that use a MCU for functions other than audio control. This device processes audio signals without using a MCU to control the volume advance rate, balance or tone. Its debounced pushbutton interface can be used with any momentary contact pushbutton switch, thus saving board space and overall system cost by eliminating costly debounce circuitry, said the company. While it was designed to alleviate MCU requirements for audio processing and control, the device can still be controlled with a MCU.

Integration in an audio processor
The new audio processor controls the wiper advance rate using the Maxim's proprietary Smart Wiper technology. The wiper advances at a rate of 4Hz after the user presses the button continuously for 1s, and at 16Hz after the button has been pressed for 4s. A mute toggle function sets all wipers to maximum attenuation and returns the wipers to their previous position when deactivated.

The new device makes the MCU or GPIO optional by integrating the audio processor controls into a debounced pushbutton interface. Maxim said the SmartWiper control increases the wiper advance rate using simple momentary contact switches, further eliminating the need for MCU intervention. Although the device does not require a MCU for audio processing, the debounced pushbutton interface can be controlled by a MCU.

The new product provides signal paths so the user can change the stereo separation or add delayed signals to improve the product's sound. This 'ambience' function toggles on or off. For greater design flexibility, added Maxim, this signal-processing path can also be used to create pseudo-stereo, thus generating a stereo signal from a monophonic source. The integrated bass-boost feature and a subwoofer output promises to improve the low-frequency sound.

Each potentiometer includes integrated suppression circuitry that ensures clickless and popless operation through all control changes such as tone, volume, power-up and power-down. A shutdown feature reduces supply current to 1.5A to extend battery life while maintaining the volume, balance and tone settings.

Range of applications
The new audio processor is primarily targeted as a complete solution for multimedia boom boxes when paired with power amps like the MAX9769. The device is also designed for multimedia-focused handheld devices such as stereo PDA/MP3 players and stereo cell phones, where the MCU can be used for functions other than simple audio control. Other applications include rear-seat entertainment controls, portable stereos, video game consoles and karaoke machines.

Available in a 4-by-4mm TQFN package, the MAX5406 is smaller than a discrete implementation. Total harmonic distortion is less than 0.01 percent and the output noise is less than 25VRMS. This low-power audio processor operates from a 2.7V to 5.25V single supply or 2.7V dual supply, and requires less than 0.5A in shutdown. Prices start at $2.17 (1,000-up, FOB USA) and samples are already available.

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