National Semiconductor PowerWise LM49251 headphone amp

National Semiconductor has released what it claims is the first stereo analog subsystem with integrated Class G headphone amplifier and automatic level control for smartphones and feature phones.

The PowerWise LM49251’s Class G headphone amp reduces the supply voltage to lower power consumption and extend audio (MP3, movies, etc) playback time.

The loudspeaker’s ALC provides designers with several options to control audio distortion levels and prevent speaker damage.

It combines a 1.4 W Class D speaker amplifier, 20 mW Class G headphone amplifier and ALC in an ultra-small 2.55 by 3.02 mm package. It consumes less than 7 mA of quiescent current at 3.3 V for the loudspeaker and headphone.

The no-clip ALC feature prevents distortion as battery voltages drop, allowing small signals to be amplified at high gains while preventing clipping of high-level signals. Its multiple inputs provide configurability for addressing different system requirements, and its mode selection, shutdown and volume are controlled through an I2C compatible interface.