Four-Channel AC'97 Audio Codec Supports Advanced Sound Positioning and AC3 Decode in the PC

Business Wire, Oct 27, 1998

AUSTIN, Texas--(BUSINESS WIRE)--Oct. 27, 1998--

The STAC9708 World's First Four-Channel AC'97 Version 2.1 Compliant Codec, Provides Multi-Codec Support for Four and Six-Channel Playback

SigmaTel Inc. has just announced production availability of their new four-channel STAC9708 2.1 compliant audio codec used in standard personal computer sound systems for record and playback capability.

The STAC9708 directly targets multi-channel PC based playback by providing four-channel output capability. The STAC9708 can be used with other multi-channel devices, such as the soon to be announced, two-channel STAC9721, to form four, six or eight-channel systems. Four-channel and six-channel systems have become essential for complete sound reproduction in modern PC games, as well as six-channel AC3-based DVD (digital video disk). The STAC9708 brings the richness of full-featured audio to the price-conscious PC industry, further blurring the line between the PC and consumer audio equipment.

The STAC9708 is one of several SigmaTel components adhering to the Intel-sponsored AC'97 Audio Codec Specification, which has standardized the audio interface for both hardware and software on the PC. The AC'97 revision 2.1 specification takes advantage of the industry-wide transition from ISA-based audio, to the more powerful PCI based and host based audio that is sweeping the PC industry. Offering real multi-channel capability, the STAC9708 allows PC designers to deliver systems with the full, rich sound stage that games and DVD playback applications were designed for. The STAC9708 is suitable for use on motherboards, PCI add-in cards and the emerging AMR card, as well as in full-featured docking stations. In addition to applications for multi-media, games and DVD playback, the STAC9708 also provides improved sound quality in set-top boxes and AC-Link enabled consumer equipment.

The STAC9708 is a full-featured audio codec, with a comprehensive multi-source mixer that can be routed to the four 18-bit DAC outputs for surround sound applications requiring four speakers. Two 18-bit ADCs provide high-quality PCM stereo record capability, and can be directed back to the PC via the AC-Link, or mixed along with standard music playback for karaoke applications. The STAC9708 supports simple front/rear four-channel playback, and can also be configured to support rear/center/bass playback with a standard AC'97 stereo codec (such as the two-channel STAC9721 codec) used for front speaker playback. The STAC9708 supports the multi-codec extension (revision 2.0 and later) of the AC'97 specification. This allows the STAC9708 to operate as the primary codec in the system, or as one of the three allowed secondary codecs. Programmable AC-Link slot assignment simplifies using the STAC9708 with other codecs.

The STAC9708 provides a built in 3D stereo enhancement (SigmaTel Surround 3D, SS3D) capability without the need for external components. Providing improved speaker separation without placing a heavy processing burden on the CPU, the STAC9708 SS3D feature gives small, closely spaced, speakers a room filling richness. Using two channels of the STAC9708, with improved virtual separation, along with center and bass support on the remaining two channels, economically produces a rich sound stage for games and DVD playback. With its 96dB SNR playback quality, the STAC9708 delivers a sound experience that was once only available from consumer audio equipment.

The STAC9708 is offered in the standard AC'97 48-pin TQFP package, over the 0 degree C to +70 degree C temperature range. Priced at $3.50 in 10kpc quantities, the STAC9708 is currently shipping in production volumes. For samples and reference design information, please contact SigmaTel directly (sales@sigmatel.com, or 512/343-6636), or visit the Web site for more information ( www.sigmatel.com ).

SigmaTel is a mixed-signal supplier of integrated circuits, including audio codecs, infrared transceivers and bridge components, as well as advanced communications technology. Serving the PC and telecommunications industries, SigmaTel is committed to the highest levels of quality and service. Founded in 1992, SigmaTel continues to experience strong growth in its business, and now has offices in Austin, Texas, and Taipei, Taiwan, as well as distributors worldwide.