ADI公司的ADAU1781是低功耗24位立体声编译码器,可编程的SigmaDSP音频处理核,低噪音DAC和ADC支持取样速率从8kHz到96kHz,扬声器能向8欧姆负载输出400mW,模拟和数字I/O电压1.8 V- 3.3 V,主要用在数码相机和数码摄像机.本文介绍了ADAU1781主要特性,方框图以及差分输入系统,模拟麦克风输入系统, 单端立体声线输入框图和立体声数字麦克风输入系统的框图,评估板EVAL-ADAU1781Z主要特性,框图,电路图,材料清单和PCB元件布局图.
The ADAU1781 is a low power, 24-bit stereo audio codec. The low noise DAC and ADC support sample rates from 8 kHz to 96 kHz. Low current draw and power saving modes make the ADAU1781 ideal for battery-powered audio applications.
A programmable SigmaDSP® core provides enhanced record and playback processing to improve overall audio quality.
The record path includes two digital stereo microphone inputs and an analog stereo input path. The analog inputs can be configured for either a pseudo differential or a single-ended stereo source. A dedicated analog beep input signal can be mixed into any output path. The ADAU1781 includes a stereo line output and speaker driver, which makes the device capable of supporting dynamic speakers.
The serial control bus supports the I2C® or SPI protocols, and the serial audio bus is programmable for I2S, left-justified, right-justified, or TDM mode. A programmable PLL supports flexible clock generation for all standard rates and available master clocks from 11 MHz to 20 MHz

ADAU1781主要特性:
24-bit stereo audio ADC and DAC
400 mW speaker amplifier (into 8 Ω load)
Programmable SigmaDSP audio processing core
Wind noise detection and filtering
Enhanced stereo capture (ESC)
Dynamics processing
Equalization and filtering
Volume control and mute
Sampling rates from 8 kHz to 96 kHz
Stereo pseudo differential microphone input
Optional stereo digital microphone input pulse-density modulation (PDM)
Stereo line output
PLL supporting a range of input clock rates
Analog and digital I/O 1.8 V to 3.3 V
Software control via SigmaStudio graphical user interface
Software-controllable, clickless mute
Software register and hardware pin standby mode
32-lead, 5 mm × 5 mm LFCSP

ADAU1781应用:
Digital still cameras
Digital video cameras

图1. ADAU1781框图

图2. ADAU1781差分输入系统框图

图3. ADAU1781模拟麦克风输入系统框图

图4. ADAU1781单端立体声线输入系统框图

图5. ADAU1781立体声数字麦克风输入系统框图

ADAU1781 SigmaDSP评估板EVAL-ADAU1781Z
This user guide explains the design and setup of the ADAU1781 SigmaDSP® evaluation board.
This evaluation board provides full access to all analog and digital I/Os on the ADAU1781. The SigmaDSP is controlled by Analog Devices, Inc., SigmaStudio™ software, which interfaces to the board via a USB connection. This evaluation board can be powered either over the USB bus or by a single 3.8 V to 6 V supply, which is regulated to the voltages required on the board. The PC board is a 4-layer design, with a single ground plane and a single power plane on the inner layers. The board contains on-board microphones and speaker, and connectors for external microphones and speaker. The master clock can be provided externally or by the on-board 12.288 MHz active oscillator.

EVAL-ADAU1781Z评估包包括:
ADAU1781 evaluation board
EVAL-ADUSB2EBZ (USBi) communications adapter
USB cable with Mini-B plug
Evaluation board/software quick-start guide
 
图6.评估板EVAL-ADAU1781Z外形图
 
图7.评估板EVAL-ADAU1781Z功能框图

图8.评估板EVAL-ADAU1781Z电路图: SigmaDSP,模拟I/O和主时钟发生

图9.评估板EVAL-ADAU1781Z电路图:数字麦克风接口

图10.评估板EVAL-ADAU1781Z电路图:串行音频数据接口

图11.评估板EVAL-ADAU1781Z电路图:电源

图12.评估板EVAL-ADAU1781Z电路图:GPIO

图13.评估板EVAL-ADAU1781Z电路图:通信接口

评估板EVAL-ADAU1781Z材料清单:



图14.评估板EVAL-ADAU1781Z PCB元件布局图