ALC655 Datasheet

Six-Channel AC’97 2.3 Audio Codec

2

Rev 1.3

1. Features

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 2.3 specifications

-Front-Out, Surround-Out, MIC-In and LINE-In

Jack Sensing

-14.318MHz- 24.576MHz PLL to save crystal

-12.288MHz BITCLK input can be consumed

-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 input: PCBEEP,

PHONE-IN

Two software selectable MIC inputs

A 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

Both Front-out and Surround-Out built-in

50mW/20

Ω amplifier

External Amplifier Power Down (EAPD)

capability

Power management and enhanced power saving

features

Stereo MIC record for AEC/BF application

Supports Power Off CD function

Adjustable VREFOUT control

Supports double sampling rate (96KHz) of DVD

audio playback

Support 48KHz of S/PDIF output is compliant with

AC’97 rev2.3 specification

Support 32K/44.1K/48KHz of S/PDIF input

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 Kara OK

mode

Configuration Panel to improve Experience of User

2. General Description

The ALC655 is a 16-bit, full duplex AC'97 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 on PC99/2001 systems. The ALC655 CODEC provides three pairs of stereo outputs with 5-Bit

volume controls, 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. The ALC655 integrates 50mW/20ohm headset audio amplifiers at

Front-Out and Surr-Out, built-in 14.318M 24.576MHz PLL and PCBEEP generator, those can save BOM costs. The ALC655

also supports the S/PDIF input and output function, which can offer easy connection of PCs to consumer electronic products, such

as AC3 decoder/speaker and mini disk devices. ALC655 supports host/soft audio from Intel ICHx chipsets as well as audio

controller based VIA/SIS/ALI/AMD/nVIDIA/ATI chipset. Bundled Windows series drivers (WinXP/ME/2000/98/NT), EAX/

Direct Sound 3D/ I3DL2/ A3D compatible sound effect utilities (supporting Karaoke, 26-kind 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. The ALC655 includes Realtek’s impedance sensing techniques that allow device loads on inputs

and outputs to be detected.