AKM AK4685 音频CODEC编译码方案

AKM 公司的AK4685是集成了四路24位ADC,两路24位DAC和立体声无电容耳机放大器的单片音频编译码器(CODEC),取样频率高达48kHz,64x过取样.ADC的动态范围为102dB,S/(N+D)为90dB,数字输出工作电压为3.0-5.25V,输入为4.75V-5.25V,电荷泵电压为3.0V-3.6V,模拟工作电压4.75V到5.25V.主要用于数字电视和家庭影院系统.本文介绍了AK4685的主要特性,方框图, 差分和单端输入外接电路图,采用单电源和双电源运放的二阶低通滤波器以及AK4685的典型应用电路.

The AK4685 is a single chip CODEC that integrates 4-channel ADC, 2-channel DAC and a stereo capacitor less headphone amplifier. The converters are designed with an Enhanced Dual Bit architecture for the ADC, and an Advanced Multi-Bit architecture for the DAC’s, enabling very low noise performance and achieving wide dynamic range. The differential analog inputs and outputs cancel noise on analog signal lines. Therefore, a stable system can be designed. The AK4685 has a dynamic range of 102dB for ADC,106dB for DAC, and is well suited for digital TV and home theater systems.

AK4685主要特性:

Asynchronous ADC/DAC1/DAC2 Operation

4ch 24bit ADC

- Differential Input

- 64x Oversampling

- Sampling Rate up to 48kHz

- Linear Phase Digital Anti-Alias Filter

- S/(N+D): 90dB

- Dynamic Range, S/N: 102dB

- Digital HPF for Offset Cancellation

- Channel Independent Digital Volume (+24/-103dB, 0.5dB/step)

- Soft Mute

Two 2ch 24bit DAC’s

- Differential/Single-end Ouput (DAC1)

- 128x Oversampling

- Sampling Rate up to 192kHz

- 24bit 8 times Digital Filter

- S/(N+D): 92dB

- Dynamic Range, S/N: 106dB

- Channel Independent Digital Volume (+12/-115dB, 0.5dB/step)

- Soft Mute