AC'97 Rev 2.3 Audio CODEC

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Lead Time 52 weeks
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Unit Price:$1.66
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Product Information

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The ALC655 is a 16-bit, full-duplex AC'97 Rev. 2.3 compatible six-channel audio CODEC designed for PC multimedia systems, including host/soft audio and AMR/CNR-based designs.

The ALC655 incorporates proprietary converter technology to meet performance requirements for PC99/2001 systems. The ALC655 CODEC provides three pairs of stereo outputs with 5-bit volume control, a mono output, and multiple stereo and mono inputs, along with flexible mixing, gain, and mute functions to provide a complete integrated audio solution for PCs.

The digital interface circuitry of the ALC655 CODEC operates from a 3.3V power supply for use in notebook and PC applications. An integrated 50mW/20ohm headset audio amplifier for Front-Out and Surround-Out, a 14.318MHz -> 24.576MHz PLL, and a PCBEEP generator cut BOM costs. The ALC655 also supports S/PDIF input and output for easy connection of PCs to consumer electronic products, such as AC3 decoders/speakers and mini-disk devices.

The ALC655 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 (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 equalizer), HRTF 3D positional audio and Sensaura™ 3DPA (optional) provide an excellent entertainment package and game experience for PC users. In addition, the ALC655 is embedded with an impedance sensing capability to detect when a device has been connected to input or output jacks.


• Multimedia PCs
• 3D PC games
• Information appliances (IA)
• Voice recognition
• Audio conferencing

Symmetry Electronics (and its e-commerce division: is an authorized Realtek distributor.


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Meets performance requirements for audio on PC99/2001 systems
Meets Microsoft WHQL/WLP 2.0 audio requirements
16-bit Stereo full-duplex CODEC with 48KHz sampling rate
Compliant with AC'97 Rev 2.3 specifications
- Front-Out, Surround-Out, MIC-In and LINE-In Jack Sensing
- 14.318MHz -> 24.576MHz PLL to eliminate crystal
- 12.288MHz BITCLK input
- Integrated PCBEEP generator to save buzzer
- Interrupt capability
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
Two software selectable MIC inputs
Dedicated Front-MIC input for front panel applications (software selectable)
Boost preamplifier for MIC input
LINE input shared with surround output; MIC input shared with Center and LFE output
Built-in 50mW/20ohm amplifier for both Front-out and Surround-Out
External Amplifier Power Down (EAPD) capability
Power management and enhanced power saving features
Supports Power-Off CD function
Adjustable VREFOUT control
Supports 48KHz S/PDIF output, complying with AC'97 Rev 2.3 specifications
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 convenience


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Realtek ALC655-LF Datasheet

Previously Viewed Products

AC'97 Rev 2.3 Audio CODEC
Part #: ALC655-LF
AC'97 Rev 2.3 Audio CODEC