Maxim公司的MAX98304是单声道3.2WD类音频放大器，提供AB类音频性能和D类效率，提供五种引脚选择的增益（0dB,3dB,6dB,9dB和12dB），3.7V的静态电流0.95mA，超低噪音19μVRMS，PSRR为90dB，开关噪音抑制，热和过流保护，低电流关断模式。主要应用在笔记本和上网本电脑，手机，平板电脑，MP3播放器，手持音频播放器，VoIP电话。本文介绍了MAX98304主要特性，功能方框图，典型应用电路图，MAX98304评估板主要特性，电路图，材料清单和PCB元件布局图。 The MAX98304 mono 3.2W Class D amplifier provides Class AB audioperformance with Class D efficiency. This device offers fiveselectable gain settings (0dB, 3dB, 6dB, 9dB, and 12dB) set by asingle gain-select input (GAIN). Active emissions-limiting, edge-rate, and overshoot controlcircuitry greatly reduces EMI. A filterless spreadspectrummodulation scheme eliminates the need for output filtering found intraditional Class D devices. These features reduce applicationcomponent count. The IC’s 0.95mA at 3.7V (1.2mA at 5V) quiescent current extendsbattery life in portable applications. The IC is available in a 9-bump (1.0mm x 1.0mm) WLP with 0.3mmpitch that is specified over the extended -40NC to +85NCtemperature range. MAX98304主要特性： Low Quiescent Current: 0.95mA at 3.7V Spread Spectrum and Active Emissions Limiting Five Pin-Selectable Gains 19μVRMS Ultra-Low Noise 90dB PSRR Click-and-Pop Suppression Thermal and Overcurrent Protection Low-Current Shutdown Mode 1.0mm x 1.0mm, 9-Bump WLP (0.3mm Pitch) Space-Saving Package MAX98304应用： Notebook and NetbookComputers Cellular Phones Tablets MP3 Players Portable Audio Players VoIP Phones 图1。MAX98304功能方框图 图2。MAX98304典型应用电路图 MAX98304评估板 The MAX98304 evaluation kit (EV kit) is a fully assembled andtested circuit board that uses the MAX98304 filterless Class Damplifier to drive a speaker in portable audio applications. The EVkit comes with a MAX98304EWL+ in a 9-bump, 0.3mm pitch wafer-levelpackage (WLP). Designed to operate from a 2.5V to 5.5V DC powersupply, the EV kit is capable of delivering 3.2W into a 4Ω load.The EV kit accepts differential or single-ended input signals. MAX98304评估板主要特性: Filterless Operation PassesRadiated Emissions with 60cm of Speaker Cable 2.5V to 5.5V Single-Supply Operation 3.2W Mono Class D Output Selectable Gain Control Differential or Single-Ended Input Low-Power Shutdown Input Fully Assembled and Tested 图3。MAX98304评估板电路图 MAX98304评估板材料清单（BOM）： 图4。MAX98304评估板元件布局图