Maxim公司的MAX98306是立体声3.7W D类放大器,具有AB类的音频性能和D类的效率.器件提供5种可供选择的增益设定(6dB, 9dB, 12dB, 15dB和18dB),工作电压5V,3.7V时的静态电流为2.0mA, 217Hz时的PSSR为83dB,具有热和过流保护,主要用在智能手机,平板电脑,MP3,手持音乐播放器和VoIP电话.本文介绍了MAX98306主要特性,方框图,典型应用电路图以及MAX98306评估板主要特性,电路图和材料清单,PCB元件布局图.
The MAX98306 stereo 3.7W Class D amplifier provides Class AB audio performance with Class D efficiency. This device offers five selectable gain settings (6dB, 9dB, 12dB, 15dB, and 18dB) set by a single gain-select input (GAIN).
Active emissions limiting, edge-rate, and overshoot control circuitry combined with a filterless spread-spectrum modulation scheme (SSM) provide excellent EMI performance while eliminating the need for output filtering found in traditional Class D devices. These features reduce application component count.
The IC’s 2.0mA quiescent current with a 3.7V supply extends battery life in portable applications.
The IC is available in a 14-pin TDFN (3mm x 3mm x 0.75mm) package specified over the extended -40NC to +85NC temperature range.

MAX98306主要特性:
Output Power 3.7W at 3I, 10% THD, 1.7W at 8I, 10% THD, with 5V Supply
Passes EMI Limit Unfiltered with Up to 12in of Speaker Cable
High 83dB PSRR at 217Hz
Spread-Spectrum Modulation and Active Emissions Limiting
Five Pin-Selectable Gains
Excellent Click-and-Pop Suppression
Thermal and Overcurrent Protection
Low-Current Shutdown Mode
Space-Saving, 3mm x 3mm x 0.75mm, 14-Pin TDFN

MAX98306应用:
Smartphones
Tablets
Cellular Phones
Accessory Speakers
MP3 Players
Portable Audio Players
VoIP Phones

图1. MAX98306方块图

图2. MAX98306典型应用电路图

MAX98306评估板
The MAX98306 evaluation kit (EV kit) is a fully assembled and tested PCB that evaluates the MAX98306 stereo 3.2W Class D amplifier. The EV kit operates from a single 2.6V to 5.5V DC power supply and is capable of delivering 3.2W into a 4I load. The EV kit accepts a differential or single-ended audio input and provides differential outputs for the speaker. The device outputs can be connected directly to a speaker load for filterless applica-tions. However, a filter can be added to ease evaluation.

MAX98306评估板主要特性:
2.6V to 5.5V Single-Supply Operation
Single-Ended or Differential Audio Input
Five Selectable Gains
Filterless Operation
Optional Class D Output Filters for Ease of Evaluation
Low-Power Shutdown Mode
Proven PCB Layout
Fully Assembled and Tested

图3.MAX98306评估板电路图
MAX98306评估板材料清单:



图4.MAX98306评估板元件布局图