The device features stereo ground-referenced headphone amplifiers using the Cirrus Logic ‘Class-W’ amplifier techniques - incorporating an innovative dual-mode charge pump architecture - to optimize efficiency and power consumption during playback.

The ground-referenced outputs eliminate headphone coupling capacitors. Both headphone and line outputs include common mode feedback paths to reject ground noise. Control sequences for audio path setup can be pre-loaded and executed by an integrated sequencer to reduce software driver development and eliminate pops and clicks via Cirrus Logic’s SilentSwitch™ technology.

The analog input stage can be configured for single-ended, pseudo-differential or fully differential inputs. Up to three stereo microphone or line inputs may be connected. The input impedance is constant with PGA gain setting. A stereo digital microphone interface is provided, which can also be mixed with the mic/line signals at the output mixers.

A dynamic range controller provides compression and level control to support a wide range of portable recording applications. Anti-clip and quick release features offer good performance in the presence of loud impulsive noises.

Common audio sampling frequencies are supported from a range of external clocks, including 3MHz, 12MHz or 24MHz. The WM8903 can operate directly from a single 1.8V switched supply. For optimal power consumption, the digital core can be operated from a 1.0V supply.