DESCRIPTION
The WM8904 is a high performance ultra-low power stereo CODEC optimised for portable audio applications.
The device features stereo ground-referenced headphone amplifiers using the Wolfson ‘Class-W’ amplifier techniques incorporating an innovative dual-mode charge pump architecture to optimise efficiency and power consumption during playback. The ground-referenced headphone and line outputs eliminate AC coupling capacitors, and both outputs include common mode feedback paths to reject ground noise.

FEATURES
3.0mW quiescent power consumption for DAC to headphone playback
DAC SNR 96dB typical, THD -86dB typical
ADC SNR 91dB typical, THD -80dB typical
2.4mW quiescent power consumption for analogue bypass playback
Control write sequencer for pop minimised start-up and shutdown
Single register write for default start-up sequence
Integrated FLL provides all necessary clocks
  -  Self-clocking modes allow processor to sleep
  -  All standard sample rates from 8kHz to 96kHz
Stereo digital microphone input
3 single ended inputs per stereo channel
1 fully differential mic / line input per stereo channel
Digital Dynamic Range Controller (compressor / limiter)
Digital sidetone mixing
Ground-referenced headphone driver
Ground-referenced line outputs
32-pin QFN package (4 x 4mm, 0.4mm pitch)
36-ball WLCSP package (2.6 x 2.5mm, 6 x 6 ball grid, 0.4mm pitch)