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AKM公司的AK4687是具有兩路輸入選擇器和線路驅動器的異步立體聲CODEC,ADC/DAC接口能接納高達24位輸入數據,并支持異步操作.24位立體聲ADC采用64x過取樣,取樣頻率高達48kHz,線性相位數字抗混淆濾波器,S/(N+D)為83dB,動態范圍99dB,而24位立體聲DAC采用128x過取樣,取樣頻率高達192kHz,24位8倍數字濾波器,S/(N+D)為95dB,動態范圍105dB.主要用在藍光影碟機, 家庭影院,DTV,數字錄音系統.本文介紹了AK4687主要特性, 方框圖,典型應用電路圖,以及評估板AKD4687-A功能,方框圖和電路圖與元件布局圖. The AK4687 is a stereo audio CODEC with 2-channel input selector and a line driver. The interfaces of ADC/DAC can accept up to 24bit input data and support asynchronous operation. The input range of the pre-amplifier, that supports 3ch stereo inputs, is selectable by external resistors. Both the input stereo selector and output drivers support ground reference 2Vrms In/Output, making it possible to remove AC-coupling capacitors and reducing external parts. The AK4687 has a dynamic range of 99dB for ADC, 105dB for DAC. It is well suitable for digital recording systems, digital TVs, Blu-ray recorders and Home theater systems. AK4687主要特性: Asynchronous ADC/DAC Operation 3:1 Capless Stereo Line Input Selector 24bit Stereo ADC - 64x Oversampling - Sampling Rate up to 48kHz - Linear Phase Digital Anti-Alias Filter - S/(N+D): 83dB - Dynamic Range, S/N: 99dB - Digital HPF for Offset Cancellation 24bit Two Stereo DAC - 128x Oversampling - Sampling Rate up to 192kHz - 24bit 8 times Digital Filter - S/(N+D): 95dB - Dynamic Range, S/N: 105dB - De-emphasis Filter High Jitter Tolerance External Master Clock Input: 256fs, 384fs, 512fs 768fs (fs=32kHz ∼ 48kHz) 128fs, 192fs, 256fs 384fs (fs=64kHz ∼ 96kHz) 128fs, 192fs (fs=128kHz ~ 192kHz) 2 Audio Serial I/F (PORT1, PORT2) - Master/Slave mode (PORT1) - I/F format PORT2: MSB, LSB justified (16/24 bit), I2S PORT1: MSB, LSB justified (16/24 bit), I2S Hardware / I2C-bus Control Operating Voltage: - Digital I/O and Charge Pump: 3.0V ∼ 3.6V - ADC Analog: 3.0V ∼ 3.6V - DAC Analog: 3.0V ∼ 3.6V Package: 48pinLQFP 
圖1.AK4687方框圖
圖2.AK4687典型連接圖(I2C控制模式, CAD0引腳= “L”,主模式)
圖3.AK4687典型連接圖(H/W控制模式, MCLK=768fs,主模式) 評估板AKD4687-A AKD4687-A is an evaluation board for AK4687, which is a single chip 24bit CODEC with a 2ch ADC and a 2ch DAC. It is possible to evaluate not only A/D and D/A of the AK4687, but also asynchronous operation characteristics. Also, the board could be connected to a digital’s audio equipment easily with S/PDIF connectors. 評估板AKD4687-A功能: Compatible with 2 types of digital audio interface - BNC (S/PDIF) input/output with DIT/DIR (AK4118A) - 10pin headers for interfacing with external data source Separate power supply or regulator power supply 10pin header for register control
圖4.評估板AKD4687方框圖
圖5.評估板AKD4687略圖
圖6.評估板AKD4687電路圖(1)
圖7.評估板AKD4687電路圖(2)
圖8.評估板AKD4687電路圖(3)
圖9.評估板AKD4687電路圖(4)
圖10.評估板AKD4687電路圖(5)
圖11.評估板AKD4687電路圖(6)
圖12.評估板AKD4687元件布局圖 詳情請見: 
akd4687-a2-03e.pdf
(1.84 MB)
ak4687_f00e.pdf
(484.21 KB)
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