The AS3560 Class G and AS3561 Class H 30-mW headphone amplifiers continuously adjust the supply rails in response to input signals, thereby minimizing power consumption. The Class G topology switches between three power rails while the Class H adapts the power rail to whatever power is needed. Both amps use differential line inputs to minimize ground noise and EMI susceptibility. They also feature a quiescent current of 1 mA with both channels enabled, a 5-mA shutdown current, SNR greater than 100 dB at 1 VRMS, and a THD of 0.02% at 16?. The AS3560 and AS3561 in 16-ball, 1.6 mm x 1.6 mm WL-CSP packages cost $0.95 and $0.98 each/1,000, respectively. AUSTRIAMICROSYSTEMS USA INC., Raleigh, NC. (919) 676-5292.