Wolfson公司的WM9081是大功率高性能低失真DAC和扬声器驱动器,D类模式的SNR为-92dB(A权重),输出0.5W时的THD+N小于0.05%,2W输出时的THD+N小于0.1%,AB类模式SNR为-97dB(A权重). WM9081最大峰值输出功率为2.6W,具有ReTune移动参数均衡器,完全可编程的滤波器系数和动态范围控制器,可用在手提导航系统,手机和平板TV.本文介绍了WM9081的主要特性,方框图, 推荐使用的外接元件以及WM9081评估板电路图和详细材料清单(BOM).
The WM9081 is designed to provide high power output at low distortion levels in space-constrained portable applications.
ReTune Mobile Parametric EQ with fully programmable coefficients is integrated for optimization of speaker characteristics. Programmable dynamic range control is also available for maximizing loudness, protecting speakers from clipping and preventing premature shutdown due to battery droop.
Digital input enables the power drivers to be located close to the speakers in multi-channel systems without the need for troublesome long analogue connections. Location of the power drivers close to the speakers also removes the need for bulky and expensive class D filters and reduces PCB track lengths, minimising emissions. The digital input can also help to minimise crosstalk to the speaker output signal from high gain microphone inputs, enhancing stability and reducing the risk of ‘howling’during speakerphone operation.
Four control interface addresses and four-channel TDM are supported to allow multiple devices to be configured and driven independently.
The device is controlled via a standard 2-wire, 3-wire, or 4-wire control interface or by hardware control pins.
图1.WM9081方框图
WM9081主要特性:
High-power, high performance DAC and speaker driver
92dB SNR (‘A-weighted’) in Class D mode
97dB SNR (‘A-weighted’) in Class AB mode
<0.05% THD+N @0.5W continuous into 4 (Class D)
<0.10% THD+N @2W continuous into 4 (Class D)
2.6W maximum peak power
ReTune Mobile Parametric Equalizer
Fully programmable filter coefficients
Programmable dynamic range controller
Boosts small signals to maximise loudness
Protects against battery droop and clipping
Speaker common mode boost
Maximises power for a given SPKVDD/AVDD ratio
Low power FLL
Provides all necessary internal clocks
32kHz to 27MHz input frequency
All common sample rates from 8kHz to 96kHz supported
Standard 2-wire, 3-wire, 4-wire and hardware control modes
Data formats: LJ, RJ, I2S, DSP, all with TDM support
Thermal shutdown interrupt
4x4 COL package (0.45mm lead pitch)
Operating temperature range: -40℃ to 85℃
WM9081应用:
Portable navigation systems
Mobile phones
Flat panel TVs
图2.推荐的WM9081外接元件
WM9081评估板
WM9081 Evaluation Board
The WM9081 is a mono DAC with an integrated high efficiency switchable class AB/D speaker amplifier capable of delivering up to 2.6W into a 4Ω load.
This evaluation platform has been designed to allow the user ease of use and give optimum performance in device measurement. The evaluation platform and documentation should be used in conjunction with the lastest version of the WM9081 datasheet, which gives device funtionality information as well as performance figures and typical applications.
WM9081
图3.WM9081评估板电路图
图4.WM9081评估板电路图(扬声器输出参考表)
WM9081评估板材料清单(BOM):
