AKM AK4688集成2路ADC及DCA的24位立体声音频CODEC设计方案
发布时间：2012-11-12 12:09
发布者：1770309616
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AKM公司的AK4688是一款立体声音频CODEC。内嵌支持异步操作的24位ADC和DAC输入/输出数据接口，通过外部电阻调节预放大器的输入范围来支持线路输入。内部集成一个电荷泵，通过3.3V单电源供电，获得一个对地2Vrms电源，以减少外部交流耦合电容及抑制电路。AK4688芯片ADC部分动态范围为99dB，DAC部分动态范围为105dB。设计方案不仅介绍了AK4688芯片ADC及DCA的特性，而且还介绍了该芯片的异步操作特性。同时，本方案提供了一个S/PDIF接口以方便连接数字音频设备。本文详细介绍了AK4688的主要特性、内部框图、应用框图以及采用AK4688芯片设计的评估开发板电路原理图及PCB Layout图。 The AK4688 is a stereo audio CODEC. The integrated ADC and DAC interfaces accept up to 24-bit input/output data and support an asynchronous operation. The input range of the pre-amplifier, that supports line inputs, is adjustable by an external resistor. A ground referenced 2Vrms output with a 3.3V single power supply is achieved by an integrated charge pump, reducing external parts such as AC-coupling capacitors and mute circuits. The ADC block of the AK4688 achieves a dynamic range of 99dB, and the DAC block achieves a dynamic range of 105dB. The AK4688 is suitable for digital recording systems, digital TVs, Blu-ray recorders and Home theater systems. AK4688主要特性 Asynchronous ADC/DAC Operation Capless Stereo Pre-amplifier for Line Input/Output 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 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 PORT1, 2: 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  ackage: 36pin QFN
图1.内部框图 采用AK4688评估板参考设计 AKD4688-A is an evaluation board for AK4688, 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 AK4688, but also asynchronous operation characteristics. Also, the board could be connected to a digital’s audio equipment easily with S/PDIF connectors. AK4688评估板参考设计的主要特性 Compatible with 2 types of digital audio interface - Optical (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 
图2.参考设计框图 AK4688评估板原理图 
图3.参考设计原理图（1） 
图4.参考设计原理图（2） 
图5.参考设计原理图（3） 
图6.参考设计原理图（4） 
图7.参考设计原理图（5） 
图8.参考设计原理图（6） AK4688评估板PCB Layout图 
详细资料如下 
ak4688_f00e.pdf
(493.1 KB)
akd4688-a-01e.pdf
(1.75 MB)
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