原标题：AKM AK4482 24位数字音频数模转换解决方案

　　akm公司的AK4482 是用于数字音频设备的高性价比的两路24位Sigma-Delta 数模转换器(DAC),采用AKM的多比特架构,具有很宽的动态范围,达到111dB,THD+N为-100dB,电源电压4.75 ∼ 5.25V,支持216kHz取样速率,非常适合BD和AC-3放大器系统.本文介绍了AK4482主要特性,方框图,典型应用框图,外接LPC滤波器电路图以及评估板AKD4482-SB框图和电路图.

　　The AK4482 is a cost-effective 24-bit DAC for digital audio equipments. The modulator uses AKM’s multi-bit architecture, delivering wide dynamic range. The AK4482 has fully differential switched-cap filter outputs, removing the need for AC coupling capacitors and increasing performance for systems with excessive clock jitter. The AK4482 support up to 216kHz sampling rate, ideal for BD and AC-3 amplifier systems. It is housed in a space saving 16pin TSSOP package.

　　AK4482主要特性:

　　 Sampling Rate: 8kHz ∼ 216kHz

　　 128 x Over Sampling (Normal Speed Mode)

　　 64 x Over Sampling (Double Speed Mode)

　　 32 x Over Sampling (Quad Speed Mode)

　　 24 Bit 8 x FIR Digital Filter

　　- High Quality Sound Short Delay Sharp Roll-off Filter (less than 6/fs)

　　- High Quality Sound Short Delay Slow Roll-off Filter (less than 6/fs)

　　- Sharp Roll-off Filter

　　- Slow Roll-off Filter

　　 Optimized Layout for Sound Quality

　　 SCF

　　 Digital De-emphasis (32kHz, 44.1kHz, 48kHz)

　　 Soft Mute

　　 Digital ATT (256 Steps)

　　 Digital I/F Format: 24Bit MSB justified, 24/20/16Bit LSB justified, I2S

　　 Master Clock: 256fs, 384fs, 512fs or 768fs (Normal Speed Mode)

　　128fs, 192fs, 256fs or 384fs (Double Speed Mode)

　　128fs or 192fs (Quad Speed Mode)

　　 THD+N: -100dB

　　 Dynamic Range: 111dB

　　 High Tolerance to Clock Jitter

　　 Power Supply: 4.75 ∼ 5.25V

　　 Package: 16pin TSSOP (6.4mm x 5.0mm)

　　图1.AK4482方框图

　　图2.AK4482典型应用电路框图

　　图3.外接2阶LPC滤波器电路图(采用运放和单电源)

　　图4.外接2阶LPC滤波器电路图(采用运放和双电源)

　　评估板AKD4482-SB

　　The AKD4482-SB is an evaluation board for AK4482, which is 192kHz sampling 24Bit ΔΣ DAC. The AKD4482-SB includes a LPF which can add differential analog outputs from the AK4482 and also has a digital interface. Therefore, it is easy to evaluate the AK4482.

　　图4.评估板AKD4482-SB方框图