Audio Codec '97

AC '97 Description

The Audio Codec specification released in 1997 [AC '97] defines the Architecture and Digital Interface, specifically designed for implementing audio and modem I/O functionality in Personal Computers. Companion specifications include the Modem Codec [MC '97], and the combined Audio/Modem Codec standard [AMC '97]. The current version of AC '97 was produced in 2002. The specification is produced and controlled by Intel. The AC-97 specification defines a recommended 48-pin QFP IC package. Of course, with an IC package, the pinout follows and defined in the standard.

AC'97 defines the Electrical interface [levels and timing], the Physical interface, and the serial interface protocol.
A 16-bit full-duplex stereo codec is defined in a 48-pin QFP package. Read more about the Quad Flat Pack package.

A MIC input line is defined. Both a main stereo output line [LINE-OUT], and a secondary stereo output line [AUX-OUT] are defined. An optional digital S/PDIF output is also specified.
A few supported configurations; 5.1 channel digital is supported via the SPDIF out line, 4 channel surround, discrete 4 channel, stereo audio, and headset audio.

There is also a Digital Controller specification, referred to as DC'97.

Note that AC97 is just one of a number of standards that Intel produced related to personal computers.

A new audio implementation has been released by Intel called High Definition Audio [HD Audio].
The Definition Audio specification is not backwards compatible with the older AC97 standard.
A description of HD Audio is located on the High Definition Audio page.
With the release of HD Audio, the slow decline of analog AC97 started, which may not even be implemented any longer.

AC97 audio is also defined on embedded computer boards such as COMexpress over a 10 pin header [a style of embedded computer board].

Refer here for a listing of IC Codec Manufacturers, or here for a complete listing of Component Manufacturers.

Description of other types of interface buses used in a personal computer; Personal Computer Buses

This topic is covered under the Buses link shown below, followed by selecting the PC Buses link next.

Editor note; The AC97 standard is not really an interface bus, but is covered because it does define a PC interface.
However that interface is really a communications protocol between ICs within a PC, or maybe just an IC specification.
Either way, the topic is covered because it was widely used within PCs, and may be referenced as an electrical interface.
So listed under the PC buses topic to answer the potential question; what is AC97.

With the introduction of HD Audio, AC97 should not be considered for new designs, unless some legacy interface is required.
Never design to an out-dated standard unless required to by the design requirements.
I would assume that the interface standard is no longer supported, or updated.


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