AKM AK4440 24位8路数模转换(DAC)方案

AKM公司的AK4440是集成了2Vrms 输出缓冲放大器的24位8路数模转换器,取样速率从8kHz到192kHz,THD+N为-94dB,动态范围为106dB,工作电压从4.5V到5.5V,主要用在消费类电子产品如DVD播放器,AV记录系统和机顶盒(STB).本文介绍了AK4440的主要特性,方框图, 并行控制模式和3线串行控制模式的典型连接图以及评估板AKD4440的主要功能,方框图和详细电路图.

The AK4440 is a 5V 24-bit 8ch DAC with an integrated 2Vrms output buffer. A charge pump in the buffer develops an internal negative power supply rail that enables a ground-referenced 2Vrms output. Using AKM’s multi bit modulator architecture, the AK4440 delivers a wide dynamic range while preserving linearity for improved THD+N performance. The AK4440 integrates a combination of switched-capacitor and continuous-time filters, increasing performance for systems with excessive clock jitter.

The 24-bit word length and 192kHz sampling rate make this part ideal for a wide range of consumer audio applications, such as DVD, AV receiver system and set-top boxes.

AK4440主要特性:

Sampling Rate Ranging from 8kHz to 192kHz

24Bit 8 times Digital Filter with Slow roll-off option

THD+N: -94dB

Dynamic Range: 106dB

High Tolerance to Clock Jitter

Single-ended Ground-referenced 2Vrms Output Buffer with 2nd order Analog LPF

Digital De-emphasis for 32, 44.1 & 48kHz sampling

Soft mute

Automatic Power-on Reset Circuit

3-wire Serial and I2C Bus μP I/F for mode setting

I/F format: MSB justified, LSB justified (16bit, 20bit, 24bit), I2S, TDM

Master clock: 256fs, 384fs, 512fs or 768fs or 1152fs (Normal Speed Mode)

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

128fs or 192fs (Quad Speed Mode)

Power Supply: +4.5 to +5.5V

Ta = -20 to 85°C

Small Package: 30 pin VSOP

图1.AK4440方框图

图2.AK4440典型连接图(并行控制模式)

图3.AK4440典型连接图(3线串行控制模式)

AK4440评估板AKD4440

The AKD4440-A is an evaluation board for the AK4440, 24bit DAC with 2Vrms line output for cost and performance based audio systems. The AKD4440-A has the interface with AKM’s A/D converter evaluation boards and the interface with digital audio systems via optical connector. Therefore, it is easy to evaluate the AK4440.

评估板AKD4440功能:

• Compatible with 2 types of input data interface

- Direct interface with AKM’s A/D converter evaluation boards via 10-pin header

- On-board AK4118 as DIR, which accepts optical or BNC Inputs

• Optical output for internal DIT

• BNC connector for an external clock input

• BNC connector for DAC output

图4.AKD4440-A 方框图

图5.评估板AKD4440电路图(1)

图6.评估板AKD4440电路图(2)

图7.评估板AKD4440电路图(3)

图8.评估板AKD4440电路图(4)

图9.评估板AKD4440电路图(5)