National Semiconductor’s Stereo Headphone Amp said to Double Audio Playback Time for Portable Devices

The LM48824’s Class G architecture significantly increases audio (MP3, mobile TV, etc.) playback time with its adaptive power supply approach that enables very low supply rails, which doubles the power-efficiency compared to typical Class AB headphone amplifiers. Additionally, the LM48824’s output noise created by ground mismatches is improved through common-mode sensing that corrects for differences between the amplifier ground and the headphone return terminal.

The LM48824 is offered in an ultra-small, 16-bump, 1.7 mm by 1.7 mm, 0.4 mm-pitch micro SMD package. It features National’s ground-referenced architecture, which saves space and minimizes system cost by eliminating the need for bulky and expensive DC blocking capacitors. The LM48824 includes a 32-step I2C compatible volume control with mute and delivers 37 mW per channel into a 16-Ohm load with less than one percent total harmonic distortion plus noise (THD+N) at 3.6V.

The LM48824’s high power supply rejection ratio (PSRR) of 105 dB at 217 Hz enables the device to operate in noisy environments without additional power supply conditioning. Its high-output impedance mode allows the LM48824’s outputs to be driven by an external source without degrading the signal.