原标题：ADI ADAU1373低功耗立体声CODEC解决方案

　　ADI公司的ADAU1373是低功耗立体声CODEC,集成了数字音频处理,支持立体声48kHz录音和播放,立体声ADC和DAC支持取样速率从 8kHz到48kHz以及数字音量控制,带PGA的八个单端或四个差分输入提供增益从-12dB到+18dB.48kHz和1.8V录音功耗7mW,播放功耗6mW,主要用在手机,平板电脑,电子书,手持媒体播放器.本文介绍了ADAU1373主要特性,方框图, 立体声D类应用电路图以及ADAU1373评估板电路图,材料清单和PCB元件布局图.

　　The ADAU1373 is a low power, stereo audio codec with integrated digital audio processing that supports stereo 48 kHz record and playback. The stereo audio ADCs and DACs support sampling rates from 8 kHz to 48 kHz, as well as a digital volume control.

　　Eight single-ended or four differential analog inputs with PGAs are provided for adjusting the gain from −12 dB to +18 dB. They can be configured for microphones or line level signals.

　　Two stereo digital microphone inputs are supported; four digital microphones can be connected in total. In addition, three serial digital audio input/output ports are provided with asynchronous sample rate converters (ASRCs) to support various sampling rates, allowing for flexible system design in mobile phone applications. The inputs can be mixed and selected before the ADC or con-figured to bypass the ADC. Two stereo DACs are included, with a flexible mixing option for routing the signals internally.

　　The analog output side consists of line outputs, headphone output, speaker output, and receiver output. Two stereo single-ended line level outputs, which can be configured as two differential outputs, are included. The headphone output is stereo true ground centered (eliminating the need for coupling capacitors), with efficient Class-G (rail switching) architecture. The efficient stereo filterless Class-D switching amplifier provides ~1 W of stereo power for speakers. The differential receiver amplifier can be used to connect the separate receiver speaker. Two PLL blocks, which can lock to the inputs from 8 kHz to 27 MHz, are included.

　　The DSP allows system designers to compensate for the real-world limitations of microphones, speakers, amplifiers, and listening environments, resulting in a dramatic improvement in perceived audio quality through equalization, multiband compression, and limiting algorithms. The SigmaStudio™ graphical development tool, which includes audio processing blocks such as filters, mixers, dynamics processors, and amplifiers for fast development of custom signal flows, is used to program the ADAU1373.

　　ADAU1373主要特性:

　　1 stereo ADC and 2 stereo DACs with sampling rates from 8 kHz to 48 kHz

　　Low power: 7 mW record, 6 mW playback, 48 kHz at 1.8 V

　　8 single-ended or 4 differential inputs with PGA

　　2 microphone bias reference voltages with current sense

　　2 stereo digital microphone inputs

　　Flexible analog input/output mixers

　　1 stereo differential or 2 stereo single-ended line outputs

　　True ground-centered stereo Class-G headphone amplifier, capable of 2 × 50 mW into 16 Ω at 1.8 V, 10% THD

　　Filterless stereo Class-D speaker amplifier, capable of 2 × 880 mW into 8 Ω at 3.6 V, 10% THD

　　Differential earpiece amplifier capable of driving 32 Ω

　　2 PLLs, supporting input clocks from 8 kHz to 27 MHz

　　I2C control interface

　　Digital audio processing

　　3 digital audio input and output ports with ASRC

　　I2S, PCM, right-justified, left-justified modes

　　4.05 mm × 3.82 mm, 81-ball, 0.4 mm pitch WLCSP package

　　−40℃ to +85℃ operating temperature range

　　ADAU1373应用:

　　Mobile phones, tablet PCs, e-books, portable media players

　　图1. ADAU1373功能方框图

　　图2. ADAU1373典型立体声D类应用电路图

　　ADAU1373评估板

　　The ADAU1373 is a low power audio codec that supports stereo record and playback. It provides eight single-ended or four differential analog inputs with PGA for adjusting the gain. The support for two stereo digital microphone inputs is provided so that, in total, four digital microphones can be connected. In addition, three serial digital audio in/out ports are provided with ASRCs to support various sampling rates at the input/output ports, allowing flexible system design.

　　The analog output side consists of line outputs, a headphone output, a speaker output, and a receiver output. The two stereo single-ended line level outputs are included, which can be configured as two differential outputs. The headphone output is stereo true-ground-centered with efficient Class-G architecture. The efficient stereo filterless Class-D switching amplifier pro-vides around 1 W stereo power for speakers. The differential receiver amplifier can be used to connect the separate receiver speaker.

　　The ADAU1373 evaluation board includes the complete application circuit for the ADAU1373. The board is featured with USBi connection to the SigmaStudio™ graphical develop-ment tool running on a host PC, which is used to program the ADAU1373.

　　Included in this user guide is a detailed description for the ADAU1373 evaluation board. It is recommended that the ADAU1373 data sheet be read along with this user guide. Full details about the part are available in the ADAU1373 data sheet, which provides more detailed information about the specifica-tions, internal block diagrams, and application guidance for the codec IC.

　　ADAU1373评估板材料清单: