Headphone amplifiers minimize power consumption

austriamicrosystems announces the AS3560 and AS3561 Stereo Headphone Amplifiers for mobile phones, portable navigation devices, music/media players, and other media devices that use headphones. These new 30 mW headphone amplifiers continuously adjust the supply rails in response to the input signal, drastically minimizing power consumption as compared to traditional Class AB amplifiers.

The AS3560 is a Class G amplifier while the AS3561 extends the power savings even more with a Class H topology. Class G topology switches between three power rails, while the Class H adapts the power rail to whatever power is needed to drive the headphone volume. Both devices use differential line inputs to minimize the effects of ground noise and EMI susceptibility, and also feature low quiescent current of 1 mA with both channels enabled. The shutdown current is extremely low at less than 5 µA.

Audio performance remains excellent with >100 dB SNR at 1 Vrms and THD of 0.02% at 16 Ω. The integrated charge pump generates a symmetric negative supply for true ground output signal levels, which saves space and minimizes system cost by eliminating the need for bulky and expensive dc blocking capacitors. An I2C bus allows volume control with 32 gain steps as well as independent channel control.

The AS3560 and AS3561 are available in a 16-ball 1.6 x 1.6 mm WL-CSP package and operate over a temperature range of -30° to
+85° C.

For more information, contact austriamicrosystems USA Inc., 5201 Great America Parkway, Suite 320, Santa Clara, CA 95054. Phone: (408) 345-1790.