Maxim MAX9879立体声D类音频功率放大方案
Maxim 公司的MAX9879是高效率立体声D类音频功率放大器,并集成了立体声无电容DirectDrive耳机放大器,以D类的效率提供AB类的性能. MAX9879能从3.7V电源向8欧姆负载提供高达715mW的功率,效率88%.D类放大器在1kHz时的THD+N低于0.04%,耳机放大器的THD+N低于0.018%,主要应用在手机和手提媒体播放器.本文介绍了MAX9879的主要特性,简化方框图, 立体声模式和单声道模式的信号通路以及典型应用电路.此外还介绍了MAX9879评估板的主要特性,详细电路图和所用元件列表.
The MAX9879 combines a high-efficiency stereo Class D audio power amplifier with a stereo capacitor-less DirectDrive® headphone amplifier. Maxim’s filterless class D amplifiers with active emissions limiting technology provide Class AB performance with Class D efficiency.
The Class D power amplifier delivers up to 715mW from a 3.7V supply into an 8ohm load with 88% efficiency to extend battery life. The filterless modulation scheme combined with active emission limiting circuitry and spread-spectrum modulation greatly reduces EMI while eliminating the need for output filtering used in traditional Class D devices.
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