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