Automotive Headphone Amplifiers from Maxim

1st May 2009

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Datasheet

Maxim has introduced the MAX13330/MAX13331 automotive, stereo headphone amplifiers. Designed for automotive entertainment systems in which board space is at a premium and high-voltage protection is paramount, these robust devices protect outputs against shorts to battery/ground and load dump up to 45V. This built-in protection circuitry eliminates the need for the discrete components that perform such protection, resulting in both space and cost savings.

They also integrate a short-circuit diagnostic output to facilitate fault analysis, and include ±15kV ESD protection (Human Body Model) on the headphone outputs. These advanced protection and diagnostic features make the MAX13330/MAX13331 the ideal choice for automotive entertainment systems.

The MAX13330/MAX13331 employ Maxim's patented DirectDrive(R) technology* to dramatically reduce BOM cost and save board space. DirectDrive headphone amplifiers produce a ground-referenced output from a single supply, and therefore do not require a DC bias voltage to be applied to the headphone-jack ground pin. This innovative approach eliminates the need for the large DC-blocking capacitors required by conventional amplifiers, thus enabling the MAX13330/MAX13331 to save up to $0.10 in cost, 150mm2 of board space, and 8mm of component height. Moreover, not using DC-blocking capacitors allows improvement of the amplifiers' low-frequency response for successful reproduction of the full range of audio bandwidth with only a 1microfarad or smaller capacitor. This capability is especially important for music playback. Ultimately, the MAX13330/MAX13331 significantly simplify end-product design while maximizing reliability.

The gain of the amplifiers can be set internally (-1.5V/V, MAX13330) or adjusted externally (MAX13331), providing flexibility in audio codec selection. Both devices operate from a single, 4V to 5.5V supply; have a low, 0.009% THD+N; and can deliver up to 75mW per channel into an 8ohm load, 100mW into a 16ohm load, or 130mW into a 32ohm load. An 80dB at 217Hz PSRR allows these devices to operate from noisy digital supplies without an additional linear regulator or filtering. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown, ensuring fast turn-on/turn-off times without audible glitches. A low-power shutdown mode reduces the supply current to < 2microamps.

Fully specified over the -40 degrees Celsius to +105 degrees Celsius AEC-Q100 Level 2 automotive temperature range, the MAX13330/MAX13331 are available in a space-saving, 4mm x 5mm, 16-pin QSOP package.