PRODUCT OVERVIEW
The AD1881A meets the Audio Codec ’97 2.0 and 2.1 Extensions. In addition, the AD1881A SoundMAX Codec is designed to meet all requirements of the Audio Codec ’97, Component Specification, Revision 1.03, © 1996, Intel Corporation, found at www.Intel.com. The AD1881A also includes some other Codec enhanced features such as the built-in PHAT Stereo 3D enhancement.
The AD1881A is an analog front end for high performance PC audio applications. The AC’97 architecture defines a 2-chip audio solution comprising a digital audio controller, plus a high quality analog component that includes Digital-to-Analog Converters (DACs), Analog-to-Digital Converters (ADCs), mixer and I/O.
The main architectural features of the AD1881A are the high quality analog mixer section, two channels of Σ∆ ADC conversion, two channels of Σ∆ DAC conversion with Data Direct Scram bling (D2S) rate generators. The AD1881A’s left channel ADC and DAC are compatible for modem applications supporting irrational sample rates and modem filtering requirements.

AC’97 2.1 FEATURES
   Variable Sample Rate
   True Line-Level Output
   Supports Secondary Codec Modes
  
AC’97 FEATURES
   Designed for AC’97 Analog I/O Component
   48-Lead LQFP Package
   Multibit ΣΔ Converter Architecture for Improved
      S/N Ratio Greater than 90 dB
   16-Bit Stereo Full-Duplex Codec
      Four Analog Line-Level Stereo Inputs for Connection
      from LINE, CD, VIDEO, and AUX
   Two Analog Line-Level Mono Inputs for Speakerphone
      and PC BEEP
   Mono MIC Input Switchable from Two External
      Sources
   High Quality CD Input with Ground Sense
   Stereo Line-Level Output
   Mono Output for Speakerphone or Internal Speaker
   Power Management Support

ENHANCED FEATURES
   Mobile Low Power Mixer Mode
   Digital Audio Mixer Mode
   Full Duplex Variable 8 kHz to 48 kHz Sampling Rate
      with 1 Hz Resolution
   PHAT™ Stereo 3D Stereo Enhancement
   Split Power Supplies (3.3 V Digital/5 V Analog)
   Extended 6-Bit Master Volume Control
   Audio Amp Power-Down Signal