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Advanced AC'97 Rev 2.3 Audio CODEC
General Description

The ALC203 is a 20-bit DAC and 18-bit ADC full-duplex AC'97 2.3 compatible stereo audio CODEC designed for PC multimedia systems, including host/soft audio, and AMR/CNR based designs.

The ALC203 incorporates proprietary converter technology to achieve a high SNR (greater than 100 dB), sensing logics for device reporting, and a Universal Audio Jack® for improved user convenience. The ALC203 AC'97 CODEC supports multiple CODEC extensions with independent variable sampling rates and built-in 3D effects. The ALC203 CODEC provides two pairs of stereo outputs with independent volume controls, a mono output, multiple stereo and mono inputs, along with flexible mixing, gain, and mute functions to provide a complete integrated audio solution for PCs.

The circuitry of the ALC203 CODEC operates from a 3.3V digital and 3.3V/5V analog power supply with EAPD (External Amplifier Power Down) control for use in notebook and PC applications. The ALC203 integrates a 50mW/20Ohm headset audio amplifier into the CODEC, saving BOM costs. The ALC203 also supports the S/PDIF out function (complies with AC'97 2.3) that offers easy connection of PCs to consumer electronic products, such as AC3 decoders/speakers and mini disk devices.

The ALC203 CODEC supports host/soft audio from Intel ICHx chipsets as well as audio controller based VIA/SIS/ALI/AMD/nVIDIA/ATI chipsets. Bundled Windows series drivers (Win98/ME/NT/2000/XP, EAX/Direct Sound 3D/I3DL2/A3D compatible sound effect utilities (supporting Karaoke, 26-kinds of environment sound emulation, 10-band equalizer), HRTF 3D positional audio and Sensaura™ 3D (optional) provide an excellent entertainment package and game experience for PC users. An internal 14.318MHz -> 24.576MHz PLL circuit generates required timing signals, eliminating the need for external crystal, whilst a built-in PCBEEP generator removes the need for an external buzzer.

  • Single chip with high S/N ratio (>100 dB)
  • Meets performance requirements for audio on PC2001 systems
  • Meets Microsoft WHQL/WLP 2.0 audio requirements
  • 20-bit DAC and 18-bit ADC resolution
  • 18-bit Stereo full-duplex CODEC with independent and variable sampling rate
  • Complies with AC'97 2.3 specifications
    • LINE/HP-OUT, MIC-IN and LINE-IN sensing
    • 14.318MHz -> 24.576MHz PLL saves crystal
    • 12.288MHz BITCLK input can be consumed
    • Integrated PCBEEP generator to save buzzer
    • Interrupt capability
    • Page registers and Analog Plug & Play
  • Support of S/PDIF out is fully compliant with AC'97 rev2.3 specifications
  • Three analog line-level stereo inputs with 5-bit volume control: LINE_IN, CD, AUX
  • High quality differential CD input
  • Two analog line-level mono input: PCBEEP, PHONE-IN
  • Supports double sampling rate (96KHz) of DVD audio playback
  • Two software selectable MIC inputs
  • +6/12/20/30dB boost preamplifier for MIC input
  • Stereo output with 6-bit volume control
  • Mono output with 5-bit volume control
  • Headphone output with 50mW/20Ohm amplifier  
  • 3D Stereo Enhancement
  • Multiple CODEC extension capability
  • External Amplifier Power Down (EAPD) capability
  • Power management and enhanced power saving features  
  • Stereo MIC record for AEC/BF application
  • DC Voltage volume control  
  • Auxiliary power to support Power Off CD
  • Adjustable VREFOUT control
  • 2 GPIO pins with smart GPIO volume control  
  • 2 Universal Audio Jacks (UAJ)® for front panel  
  • Supports 32K/44.1K/48K/96KHz S/PDIF output  
  • Supports 32K/44.1K/48KHz S/PDIF input  
  • Power support: Digital: 3.3V; Analog: 3.3V/5V
  • Standard 48-Pin LQFP Package  
  • EAX™ 1.0 & 2.0 compatible  
  • Direct Sound 3D™ compatible  
  • A3D™ compatible  
  • I3DL2 compatible  
  • HRTF 3D Positional Audio
  • Sensaura™ 3D Enhancement (optional)  
  • 10 Bands of Software Equalizer  
  • Voice Cancellation and Key Shifting in Kareoke mode
  • AVRack® Media Player
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Reference Designs


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