AC'97 (short for Audio Codec '97; also MC'97, short for Modem Codec '97) is Intel Corporation's Audio Codec standard developed by the Intel Architecture Labs in 1997, and used mainly in motherboards, modems, and sound cards.
Audio components integrated into chipsets consist of two components: an AC'97 digital controller (DC97), which is built into the I/O Controller Hub (ICH) of the chipset, and an AC'97 audio and modem codecs, which is the analog component of the architecture. AC'97 defines a high-quality, 16- or 20-bit audio architecture with surround sound support for the PC. AC'97 supports a 96 kHz sampling rate at 20-bit stereo resolution and a 48 kHz sampling rate at 20-bit stereo resolution for multichannel recording and playback.
AC97 defines a maximum of 6 channels of analog audio output, whereas HD Audio has the capability to define many more channels but in practice most motherboards only allow for up to 8 channels.
Integrated audio is implemented with the AC'97 Codec on the motherboard, a Communications and Networking Riser (CNR) card, or an audio/modem riser (AMR) card.
In 2004 AC'97 was superseded by Intel High Definition Audio (HD Audio).
AC'97 has had several revision:
- AC'97 1.x compliant indicates fixed 48K sampling rate operation (non-extended feature set)
- AC'97 2.1 compliant indicates extended audio feature set (optional variable rate, multichannel, etc.)
- AC'97 2.2 compliant indicates extended audio, enhanced riser audio support, and optional S/PDIF
- AC'97 2.3 compliant indicates extended configuration information and optional jack sensing support
AC '97 v2.3 enables Plug and Play audio for the end user. This revision provides means for the audio codec to supply parametric data about its analog interface much like Intel High Definition Audio.
Codec chips have an AC97 interface on one side and analog audio interface on the other. They are usually small square chips with 48 pins (48-pin QFP package). They are D/A and A/D or only D/A.
- Analog Devices AD1819B, 1881A, 1885, 1886, 1887, 1980, 1981, 1985
- AKM (Asahi Kasei Microsystems) AK 4540, 4543, 4544A, 4545
- Avance Logic (now Realtek) ALC201A, ALC202/A, ALC650, ALC655, ALC658, ALC101, ALC202A, ALC250, ALC850, ALC888
- Conexant Cx20468 - with a modem
- Cirrus Logic CrystalWare 4236, CrystalClear SoundFusion CS4297, CS4299
- Crystal Semiconductors CS4205, CS4202
- C-Media CMI9738, 9739, 9761, 9880
- ESS ES1988 (with a modem)
- Empia EMP202 (2 channel, 20-bit DAC and 20-bit ADC, full duplex AC'97 2.2 compatible stereo audio CODEC)
- Intersil HMP9701 (obsolete, 48 kHz fixed samplerate)
- National Semiconductor LM4550, LM49321, LM49350, LM49352
- Philips UCB 1400 (with touchscreen controller)
- Realtek ALC5610 ALC5611
- SigmaTel (now IDT) C-Major STAC 9460 (D/A only), 9461, 9462, 9463, 9200, 9202, 9250, 9251, 9220, 9221, 9223, 9750
- Silicon Image Si3024 (mono only)
- TriTech Microelectronics TR28022, 28026
- Yamaha YMF 743, 752, 753
- VIA VT1612, VT1616 (VIA Six-TRAC Vinyl Audio), VT82C686
- VIA AC97 codec incorporated into VT82C686A South Bridge ( VT82C686A )
VIA AC97 codec incorporated into VT82C686B South Bridge ( VT82C686B )
VIA AC97 codecs incorporated into VT8233, VT8233A, VT8233C, VT8235 and VT8237 South Bridges ( VT1612A VT8233/A/C VT8233/VT8233A/VT8233B/VT8235/VT8237 VT8235 VT8235CE VT8237 )
VIA Six-TRAC (VT1616 Codec) ( VT1616 )
VIA Vinyl Eight-TRAC (VT1617 Codec) ( VT1617 )
VIA AC97 codec incorporated into VT8231 South Bridge ( VT8231 )
VIA VT1612A audio codec ( VT1612A ) - Winbond W83971
- Wolfson Microelectronics WM9701, WM9703, WM9704, WM9705 (w/touchscreen), WM9707, WM9708, WM9709 (DAC only), WM9711, WM9712 (w/touchscreen), WM9713 (w/touchscreen), WM9714
