IDT公司的ACS422x00是低功耗高保真24位立体声CODEC.器件还集成了DDX D类扬声器放大器,真正无电容的耳机放大器和四个可编程的系统PLL.其中的DAC具有102dB SNR, THD+N优于-82dB,而ADC具有90dB SNR, HD+N优于-80dB.器件具有3D立体声增强效果,1W时的效率大于80%,主要用在平板电脑,PND,PMP,手提投映仪和音箱等.本文介绍了ACS422x00主要特性,方框图, 输出和输入音频处理框图以及参考设计电路图.
PORTABLE CONSUMER CODEC LOW-POWER, HIGH-FIDELITY INTEGRATED CODEC
The ACS422x00 is a low-power, high-fidelity integrated CODEC targeted at portable applications such as tablet computers, personal navigation devices, portable projectors and speaker docks. In addition to a high-fidelity low-power CODEC, the device integrates a DDXTM class-D speaker amplifier, a true cap-less headphone amplifier, and four programmable system PLLs to enable the timing management of the systems applications processor, USB interface, secondary audio and other subsystems.
Beyond high-fidelity for portable systems, the device offers an enriched “audio presence” through built-in audio processing capability The ACS422x00 has been designed with rapid customization in mind. IDT is able to rapidly provide varying levels of integration, additional audio processing, more or fewer PLLs, etc, according to the needs of large markets or customers.

ACS422x00主要特性:
• High fidelity 24-bit stereo CODEC
• DAC 102dB SNR; THD+N better than -82dB
• ADC 90dB SNR, THD + N better than -80dB
• Built in audio controls and processing
• 3D stereo enhancement
• Dual (cascaded) stereo 6-band parametric equalizers
• Programmable Compressor/Limiter/Expander
• Psychoacoustic Bass and Treble enhancement processing
• Filterless Stereo DDXTM Class D Speaker Driver
• 1W/channel (8ohm) or 2W/channel (4 ohm), 0.05% THD+N typical
• Tri-state DDXTM Class D achieves low EMI and high efficiency
• >80% efficiency at 1W
• Spread spectrum support for reduced EMI output power mode
• Anti-Pop circuitry
• On-chip true cap-less headphone driver
• 40 mW output power (16ohm)
• Charge-pump allows true ground centered outputs
• SNR of 102dB
• I2S data interface
• Microphone/line-in interface
• Analog microphone or line-in inputs
• Digital microphone (ACS422D00)
• Automatic level control
• 4 on-chip low-jitter PLLs for internal and system timing
• Multiple frequency options
• Spread spectrum support
• Low power with built in power management
• 1.7 V CODEC supports 1Vrms
• Very low standby and no-signal power consumption
• 1.8V digital / 1.7V analog supply for low power
• 2-wire (I2C compatible) control interface
• 68-pin dual row 6x6 mm Thermal Leadless Array package

ACS422x00目标应用:
• Tablet Computers
• Portable Navigation Devices
• Personal Media Players
• Portable Projectors
• Speaker Docks

图1.ACS422x00方框图

图2.ACS422x00输出音频处理框图

图3.ACS422x00输入音频处理框图

图4.ACS422x00参考设计电路图(1)

图5.ACS422x00参考设计电路图(2)

图6.ACS422x00参考设计电路图(3)