Maxim 公司的MAX9856是高性能低功耗立体声CODEC,适用于手机,MP3,PMP或其它手持多媒体设备. MAX9856提供麦克风输入放大器和灵活的输入选择,信号混合和自动增益控制(AGC).电源1.8V时能向32欧姆耳机提供30mW输出,线输出为1Vrm. MAX9856集成了18位立体声DAC(取样频率96kHz)和ADC(取样频率48kHz),主时钟频率从10MHz到60MHz.本文介绍了MAX9856的主要特性,方框图,以及MAX9856评估套件的主要特性,所用元件列表以及详细的电路图.
The MAX9856 is a high-performance, low-power stereo audio CODEC designed for MP3, personal media players (PMPs), or other portable multimedia devices. Using on-board stereo DirectDrive headphone amplifiers, the CODEC can output 30mW into stereo 32ohm headphones while operating from a single 1.8V power supply. Very low 9mW playback power consumption makes it an ideal choice for battery-powered applications.
The MAX9856 provides microphone input amplifiers, plus flexible input selection, signal mixing, and automatic gain control (AGC). Comprehensive loadimpedance sensing allows the MAX9856 to autodetect most common audio and audio/video headset and jack plug types.
Outputs include stereo DirectDrive line outputs and DirectDrive headphone amplifiers. The stereo ADC can convert audio signals from either internal or external microphones that can be configured for single-ended or differential signal inputs. Line inputs can be configured as stereo, differential, or mono and fed through one channel of the microphone path. The analog inputs selected can be gain ranged or mixed with other input sources prior to conversion to digital. The ADC path also features programmable digital highpass filters to remove DC offset voltages and wind noise.
The MAX9856 supports all common sample rates from 8kHz to 48kHz in both master and slave mode. The serial digital audio interfaces support a variety of formats including I2S, left-justified, and PCM modes.
The MAX9856 uses a thermally efficient, space-saving 40-pin, 6mm x 6mm x 0.8mm TQFN package.
MAX9856主要特性:
1.71V to 3.6V Single-Supply Operation
Stereo 30mW DirectDrive Headphone Amplifier
Stereo 1VRMS DirectDrive Line Outputs (VDD = 1.8V) and Stereo Line Inputs
Low-Noise Stereo and Mono Differential Microphone Inputs with Automatic Gain Control and Noise Quieting
9mW Playback Power Consumption (VDD = 1.8V)
91dB 96kHz 18-Bit Stereo DAC
85dB 48kHz 18-Bit Stereo ADC
Supports Any Master Clock Frequency from 10MHz to 60MHz
ADCs and DACs Can Run at Independent Sample Rates
Flexible Audio Mixing and Volume Control
Clickless/Popless Operation
Headset Detection Logic
I2C Control Interface
MAX9856应用:
MP3 Players
Personal Media Players
Handheld Gaming Consoles
Cellular Phones
图1.MAX9856功能方框图
MAX9856评估套件
The MAX9856 evaluation kit (EV kit) consists of a MAX9856 evaluation board and software. The MAX9856 EV kit is a fully assembled and tested printed-circuit board (PCB) that evaluates the MAX9856 highperformance, low-power stereo audio CODEC with microphone inputs, DirectDrive headphone amplifiers, and stereo line outputs. The EV kit is designed to send and receive digital audio data in the Sony/Philips digital interface (S/PDIF) format and can be optionally configured to communicate using generic digital audio or I2Scompatible signals. The EV kit provides RCA jacks for connecting analog input signals, analog output signals, and digital S/PDIF signals. A 3.5mm headphone jack provides easy connection of headphones to the circuit board. Another 3.5mm microphone jack provides easy connection of microphones to the circuit board.
The MAX9856 EV kit includes Windows 2000/XP/Vista-compatible software that provides a simple graphical user interface (GUI) for exercising the features of the
MAX9856. The EV kit is connected to a PC through a USB cable.
MAX9856评估套件主要特性:
USB Connectivity (No External Power Supply Required)
Electrical S/PDIF Input/Output (with TOSLINK Option)
On-Board 12MHz Crystal Clock Oscillator
One On-Board S/PDIF Digital Audio Receiver
One On-Board S/PDIF Digital Audio Transmitter
On-Board Power-Management IC
Isolation Header for Direct Communication with the MAX9856 I2C and Digital Audio Interfaces
Easy-to-Use Menu-Driven Software
Fully Assembled and Tested
Windows 2000/XP/Vista-Compatible Evaluation Software
MAX9856评估板元件列表:
图2.MAX9856评估板最少元件配置图
图3.MAX9856评估套件电路图(1)
图4.MAX9856评估套件电路图(2)
图5.MAX9856评估套件电路图(3)
图6.MAX9856评估套件电路图(4)
图7.MAX9856评估套件电路图(5)
图8.MAX9856评估套件电路图(6)
图9.MAX9856评估套件电路图(7)
