Stand-alone audio processor IC boosts boom boxes

Sunnyvale, Calif.&#8212Maxim says its MAX5406 is the industry's most highly integrated audio processor chip. The device, targeted as a complete solution for boom boxes when paired with power amps like the MAX9769, can also be applied to multimedia devices such as stereo PDA/MP3 players and stereo cell phones. Other applications include rear-seat entertainment controls, portable stereos, video game consoles, and karaoke machines.

The stand-alone chip, working from a single supply (2.7 to 5.25 volts) or dual supply (&plusmn2.7 V) integrates all the op amps and potentiometers for control of standard audio functions (balance, volume, tone, treble, bass, bass boost, and ambience). The device’s debounced pushbutton interface, in lieu of a microcontroller, controls all functions (optionally, a microcontroller can be used).

Users control the wipers' advance rate using the company’s Smart Wiper technology. The wipers advance at a rate of 4 Hz for four seconds after the user presses the button for 1 second, and in 16 Hz steps thereafter. A mute toggle function sets all wipers to maximum attenuation and returns the wipers to their previous position when deactivated. Integrated bass and treble filter circuitry implements the Baxandall response. The bass and treble corner frequencies are set using small external ceramic capacitors.

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 1.5 mA to extend battery life while maintaining the volume, balance, and tone settings.

Users can also change the stereo separation or add delayed signals. The “ambience” function toggles on or off. For greater design flexibility, this signal-processing path can also be used to create pseudo-stereo to create a stereo signal from a monophonic source. A bass-boost feature and a subwoofer output are also included to improve low-frequency response. Total harmonic distortion over the audio range is less than 0.01 percent and output noise is less than 25 mV RMS.

Additional features include integrated passive filters to automatically reject any RF interference that can couple into the audio path of WLAN, BT, and mobile phone products.

Click here to access the preliminary datasheet. The MAX5406, in a 7-by-7 mm TQFN package, is priced starting at $2.17 each (1000-up, FOB USA). Samples are available now.

Maxim Integrated Products , 1-888-629-4642,

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