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Professional AC'97 Rev 2.3 Audio CODEC
General Description

The ALC250 is a 20-bit DAC and 18-bit ADC full duplex AC'97 Rev 2.3 compatible stereo audio CODEC designed for PC multimedia systems, including host/soft audio and AMR/CNR based designs.

The ALC250 incorporates proprietary converter technology to achieve a high SNR (100 dB), sensing logics for device reporting, and a Universal Audio Jack® for improved user experience. The ALC250 AC'97 CODEC supports multiple CODEC extensions with independent variable sampling rates and built-in 3D effects. Two pairs of stereo outputs with independent volume controls, a mono output, and multiple stereo and mono inputs, along with flexible mixing, gain, and mute functions provide a complete integrated audio solution for PCs.

The circuitry of the ALC250 CODEC operates from a 3.3V digital power and 5V analog power supply with EAPD (External Amplifier Power Down) control for use in notebook and PC applications. The ALC250 integrates a 50mW/20Ohm headset audio amplifier into the CODEC, saving BOM costs. It also supports the SPDIF out function (complies with AC'97 Rev 2.3) that offers easy connection of PCs to consumer electronic products, such as AC3 decoders/speakers and mini disk devices.

The ALC250 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 (Windows 98/ME/NT/2000/XP), EAX/ Direct Sound 3D/ I3DL2/ A3D compatible sound effect utilities (supporting Karaoke, 26 types of environment sound emulation, 10-band software equalizer), HRTF 3D positional audio and Sensaura™ 3DPA (optional) provide an excellent entertainment package and game experience for PC users. An integrated 14.318MHz -> 24.576MHz PLL circuit generates the required clock and eliminates the need for an external crystal. In addition, the ALC250 is embedded with a 7-band digital hardware equalizer to optimize speaker frequency response for mobile PCs.

  • Built-in 7-band digital hardware equalizer to optimize speaker response
  • Single chip with high S/N ratio (100 dB)
  • Meets performance requirements for audio on PC99/2001 systems
  • Meets Microsoft WHQL/WLP 2.0 audio requirements
  • 20-bit DAC and 18-bit ADC resolution
  • Complies with AC'97 Rev 2.3 specifications
    • LINE/HP-OUT, MIC-IN and LINE-IN sensing
    • 14.318MHz -> 24.576MHz PLL to eliminate crystal
    • S/PDIF output
    • 12.288MHz BITCLK input
    • Integrated PCBEEP generator to save buzzer
    • Interrupt capability
    • Page registers and Analog Plug & Play
  • 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 inputs: PCBEEP, PHONE-IN
  • Supports double sampling rate (96KHz) for 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 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™ 3DPA Enhancement (optional)
  • 10-band software equalizer
  • Voice cancellation and key shifting in Karaoke mode
  • AVRack® Media Player
  • Configuration Panel for improved user experience
  • Multimedia PCs
  • 3D PC games
  • Information appliances (IA)
  • Voice recognition
  • Audio conferencing
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