Headphone amplifier decreases board space

Sunnyvale, Calif.—Maxim Integrated Products has introduced the MAX9729 headphone amplifier based on DirectDrive technology that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors.

Integrated software-enabled bass boost and volume control makes the MAX9729 suitable for portable audio applications. A beep input with independent attenuation control and a 3:1 stereo input multiplexer further reduce system cost and board space. The MAX9729 also includes Maxim's click-and-pop suppression circuitry, which eliminates audible transients during power and shutdown cycles.

The MAX9729's bass boost feature improves audio reproduction when using inexpensive headphones. Integrated volume control features 32 discrete volume levels and uses an electronic volume-ramping function to ensure smooth volume transitions during shutdown cycles and input selection.

Eight different programmable maximum gain settings allow a wide range of input-signal levels. A 3:1 multiplexer and mixer allow the selection and summation of multiple stereo input-signal sources. Bass boost, volume control, gain settings, and input selection are all conveniently controlled through the I&sup2C-compatible serial interface.

The MAX9729 delivers 52-mW into a 32-ohm load, low 0.03% THD+N, and high 90-dB PSRR. This device is available in a 28-pin TQFN package (5mm x 5mm x 0.8mm) that is specified over the -40°Celsius to +85 °C extended temperature range.

Pricing: Starts at $0.80 (1000-up, FOB USA).
Availability: Now; an evaluation kit is available.


Maxim Integrated Products, 1-800-998-8800,

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