AKM公司的AK4688是立體聲音頻CODEC,集成了具有24位輸入/輸出數據的ADC和DAC接口,支持異步操作.64x過取樣,取樣速率高達48kHz,線性相位數字抗混淆濾波器,S/(N+D)為83dB,動態范圍105dB,S/N為99dB, 3.3V單電源輸出達2Vrms,適合用于數字錄音系統,DTV,藍光記錄儀和家庭影院.本文介紹了AK4688主要特性,方框圖,典型應用電路以及評估板AKD4688-A主要功能,方框圖,電路圖和PCB元件布局圖.

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

?? Package: 36pin QFN

圖1.AK4688方框圖

圖2.AK4688典型應用框圖(I2C控制模式, CAD0 引腳= “L”, 主模式)

圖3.AK4688典型應用框圖(H/W控制模式, MCLK=768fs, 主模式)

評估板AKD4688-A

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.

評估板AKD4688-A功能:

? 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

圖4.評估板AKD4688-A框圖

圖5.評估板AKD4688-A電路圖(1)

圖6.評估板AKD4688-A電路圖(2)

圖7.評估板AKD4688-A電路圖(3)

圖8.評估板AKD4688-A電路圖(4)

圖9.評估板AKD4688-A電路圖(5)

圖10.評估板AKD4688-A電路圖(6)

圖11.評估板AKD4688-A PCB元件布局圖(頂層)

圖12.評估板AKD4688-A PCB元件布局圖(底層)
詳情請見:
http://www.asahi-kasei.co.jp/akm/en/product/ak4688/akd4688-a-01e.pdf
和
http://www.asahi-kasei.co.jp/akm/en/product/ak4688/akd4688-a-01e.pdf