Wolfson公司的WM8910是高性能超低功耗立体声DAC,采用Wolfson的W类放大器技术,具有立体声参考地耳机放大器,不需要耳机输出耦合电容,典型的SNR为96dB,THD为-86dB,DAC到耳机播放的功耗为4.5mW,取样频率从8kHz到96kHz,单个寄存器用来写入默认的起动顺序,集成的FLL提供了所有`必要的时钟,主要用在手提媒体播放器,多媒体手机和手持游戏机.本文介绍了WM8910主要特性,方框图以及外部元件连接图.
The WM8910 is a high performance ultra-low power stereo DAC 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 SilentSwitch? technology.
The analogue input stage can be configured for single ended, pseudo-differential or fully differential inputs. Up to 2 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 FLL.
The WM8910 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.
WM8910主要特性:
4.5mW power consumption for DAC to headphone playback
DAC SNR 96dB typical, THD -86dB 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
2 single ended inputs per stereo channel
1 pseudo differential input per stereo channel
1 fully differential mic 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)
WM8910应用:
Portable multimedia players
Multimedia handsets
Handheld gaming
图1. WM8910方框图
图2.推荐的WM8910外部元件连接图
