Date: 17/08/2010

Class G and class H head phone amplifiers from austriamicrosystems

austriamicrosystems (AMS) has announced low power consuming audio amplifier IC chips AS3560 and AS3561 for driving head phone speakers in hand held audio/video players and mobile phones. With class D, G, and H type amplifers taking the mainstage, the old Class AB amplifiers can better be called as obsolete technology. Class AB is hugely in-efficient compared to class D. G and H.

The AS3560 is a Class G amplifier IC where as AS3561 is a Class H amplifier IC. Class G topology switches between 3 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 low at less than 5 µA.

AMS says audio performance remains excellent with >100 dB SNR @ 1 Vrms and THD of 0.02 % at 16 ?, making the AS3560/AS3561 the best such devices available for power consumption and audio performance. 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.

“Class G gives you all the benefits of a linear headphone driver in terms of sound quality, while minimizing the power loss“, commented Oliver Jones, austriamicrosystems’ Marketing Manager for Audio products. “This topology is without doubt the most efficient way to drive a headphone for cost vs. performance. But Class H goes even further, squeezing every last minute out of the battery.“

Package: 16-ball 1.6x1.6 mm WL-CSP

Operating temperature range: -30 to +85 °C

Price:
The AS3560 is priced at US$0.95 for 1000 peice quantities
The AS3561 is priced at US$0.98 for 1000 piece quantities

Availability: Now