Описание
The WM8903 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 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 Wolfson’s Silent Switch technology. The analogue input stage can be configured for single ended or differential inputs. Up to 3 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, either directly or generated via the Frequency Locked Loop (FLL). 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.
- 4.5mW power consumption for DAC to headphone playback
- DAC SNR 96dB typical, THD -86dB typical
- ADC SNR 92dB typical, THD -80dB typical
- Control 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
- Stereo differential line driver for direct interface to WM9001 speaker driver
- 40-pin QFN package (5x5mm)
