Wolfson Microelectronics has a low power audio codec with Class G, ground referenced headphone driver.

The device's Class G architecture is implemented by powering the headphone amplifier with a dual input, level shifting, charge pump. This generates both the positive and negative power supply rails, ground referencing the headphone outputs.

Automatic control of the charge pump maintains the most power efficient operating state during headphone playback. This is done with no intervention required from the operator or host software.

The ground-referenced Class G headphone amplifier also eliminates many sources of pops & clicks during power up, power down, mute and unmute to deliver the high quality audio performance expected by today's consumer.

Designated the WM8900, the chip's quiescent headphone playback power consumption is under 6mW in voice mode and under 11mW in Hi-Fi mode.

As a result, said the supplier, when using a typical 300mAH battery, the WM8900-based design can extend battery life by up to 11 hours during headphone music playback at a typical 2mW/ch listening level.

The device is offered in a low profile 0.55mm high 40-pin QFN package.

See www.wolfson.com