The WM8731 is a low power stereo codec with an integrated headphone driver. Stereo line and mono microphone level audio inputs are provided, along with a mute function, programmable line level volume control and a bias voltage output suitable for an electric type microphone. Digital audio input word lengths from 16-32 bits and sampling rates from 8 kHz to 96 kHz are supported. Stereo audio outputs are buffered for driving headphones from a programmable volume control, line level outputs are also provided along with anti-thump mute and power up/down circuitry. The device is controlled via a 2 or 3 wire serial interface. The interface provides access to all features including volume controls, mutes, de-emphasis and extensive power management facilities.