原标题：Maxim MAX98089带扬声器保护的音频CODEC解决方案

　　Maxim 公司的MAX98089是带扬声器保护的高性能低功耗的音频CODEC,具有101dB DR的立体声DAC(8kHzD 类放大器,以及高效的H类耳机放大器.本文介绍了MAX98089主要特性,方框图,扬声器信号处理方框图以及采用模拟麦克风输出和旁路开关和采用数字麦克风输出和接收放大器的应用电路图,MAX98089评估板主要特性,简化方框图,软件主窗口和电路图,材料清单与PCB元件布局图.

　　The MAX98089 is a full-featured audio codec whose high performance and low power consumption make it ideal for portable applications.

　　Class D speaker amplifiers provide efficient amplification for two speakers. Low radiated emissions enable com-pletely filterless operation. Integrated bypass switches optionally connect an external amplifier to the transducer when the Class D amplifiers are disabled.

　　The IC features a stereo Class H headphone amplifier that utilizes a dual-mode charge pump to maximize effi-ciency while outputting a ground referenced signal that does not require output coupling capacitors.

　　The IC also features a mono differential amplifier that can also be configured as a stereo line output.

　　Two differential analog microphone inputs are available as well as support for two PDM digital microphones. Integrated switches allow for an additional microphone input as well as microphone signals to be routed out to external devices. Two flexible single-ended or differential line inputs may be connected to an FM radio or other sources.

　　Integrated FlexSoundK technology improves loudspeak-er performance by optimizing the signal level and fre-quency response while limiting the maximum distortion and power at the output to prevent speaker damage. Automatic gain control (AGC) and a noise gate optimize the signal level of microphone input signals to make best use of the ADC dynamic range.

　　The device is fully specified over the -40NC to +85NC extended temperature range.

　　MAX98089主要特性:

　　5.6mW Power Comsumption (DAC to HP at 97dB DR)

　　101dB DR Stereo DAC (8kHz < fS < 96kHz)

　　93dB DR Stereo ADC (8kHz < fS < 96kHz)

　　Stereo Low EMI Class D Amplifiers 1.7W/Channel (8I, VSPK_VDD = 5.0V) 2.9W/Channel (4I, VSPK_VDD = 5.0V)

　　Efficient Class H Headphone Amplifier

　　Differential Receiver Amplifier/Stereo Line Outputs

　　2 Stereo Single-Ended/Mono Differential Line Inputs

　　3 Differential Microphone Inputs

　　FlexSound Technology 5-Band Parametric EQ Automatic Level Control (ALC) Excursion Limiter Speaker Power Limiter Speaker Distortion Limiter Microphone Automatic Gain Control and Noise Gate Dual I2S/PCM/TDM Digital Audio Interfaces

　　Asynchronous Digital Mixing

　　Supports Master Clock Frequencies from 10MHz to 60MHz

　　RF Immune Analog Inputs and Outputs

　　Extensive Click-and-Pop Reduction Circuitry

　　Available in 63-Bump WLP Package (3.80mm x 3.30mm, 0.4mm Pitch) and 56-Pin TQFN Package (7mm x 7mm x 0.75mm)

　　图1.MAX98089方框图

　　图2.MAX98089扬声器信号处理方框图

　　图3.MAX98089采用模拟麦克风输出和旁路开关的应用电路图

　　图4.MAX98089采用数字麦克风输出和接收放大器的应用电路

　　MAX98089评估板

　　The MAX98089 evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX98089 audio codec. The IC is an integrated audio codec includ-ing microphone amplifiers, line amplifiers, an earpiece amplifier, stereo Class D amplifiers, stereo DirectDriveM headphone amplifiers, and digital signal processing. The EV kit also includes Windows XPM-, Windows VistaM-, and WindowsM 7-compatible software that provides a simple graphical user interface (GUI) for exercising the features of the IC.

　　The EV kit provides access to all analog and digital inputs/outputs on the IC. To enable easy connection to a wide range of audio sources, audio devices are included to convert both USB data and S/PDIF data to I2S.

　　The EV kit integrates a MAXQ2000 microcontroller to enable I2C communication with devices on the EV kit. The EV kit software, running on a Windows PC, commu-nicates with the EV kit over a standard USB port. The EV kit software provides an intuitive interface to exercise the functions of the IC.

　　The EV kit comes with a MAX98089EWY+ installed.

　　MAX98089评估板主要特性:

　　2.8V to 5.5V Single-Supply Operation

　　Proven Audio PCB Layout

　　On-Board USB-to-I2C Interface Circuit

　　On-Board USB-to-I2S Converter

　　On-Board S/PDIF Transceiver

　　On-Board Clock Source

　　On-Board Digital Microphone

　　Evaluates the MAX98089EWY+ in a 3.8mm x 3.3mm, 63-Bump WLP Package

　　Windows XP-, Windows Vista-, and Windows 7-Compatible Software

　　Proven PCB Layout

　　Fully Assembled and Tested

　　图5.MAX98089评估板简化方框图

　　MAX98089评估板材料清单: