SigmaTel Showcases 8-Channel Theater-Quality Audio Solutions With Intel Audio Studio.

SAN FRANCISCO -- SigmaTel Inc. (NASDAQ:SGTL), a leading supplier of audio codecs for PC applications, announced that they will be highlighting the STAC9220 and STAC9221 8-channel High Fidelity Codecs during the Intel Developer Forum. Both audio codecs support the Intel(R) High Definition Audio (HD Audio) standard. The STAC9221 codec will be featured on versions of Intel(R) Desktop Boards with the Intel(R) 945 & 955 Express Chipset unveiled by Intel at the show. This product enables surround sound theater quality 7.1 audio for the high-end PC, Media Center applications and convergence devices such as Digital Media Adapters (DMA) and Media Center Extenders. The STAC9220 enables high definition

audio for the mainstream desktop PC within the Intel Audio Studio interface.

SigmaTel's audio codec solutions, as well as portable digital audio demonstrations, are featured in the Civic Room on floor two, at the Argent Hotel in San Francisco during the Intel Developer Forum March 1-3.

"SigmaTel's product excellence is recognized by being selected as the featured audio component on this Intel motherboard design," said Phil Pompa, vice president of Integrated Components Group at SigmaTel. "We feel it is our obligation as a market leader to be involved and to influence the standards associated with consumer and computer audio. This Intel design is 'SigmaTel Certified' for high audio quality."

The STAC9221 sets the standard for high performance by providing 8-channels of true 24-bit audio with a 105dB SNR (Signal-to-Noise Ratio). This level of performance enables theater-quality 7.1 surround sound in PCs and PC-like devices that continue to move into the living room alongside or in place of traditional consumer electronics gear. The STAC9221 incorporates an ADAT(R) Lightpipe interface allowing connectivity to professional audio equipment.

The STAC9220 provides 95dB SNR performance setting the standard for the high volume, mainstream desktop PC and high end notebook PCs. Both products feature SigmaTel Universal Jacks(TM) technology for internal jack sense capabilities, S/PDIF input and output, integrated headphone amplifiers and microphone boost circuits. Both products are supported with SigmaTel's advanced software capabilities including drivers for the Windows operating system and advanced signal processing plug-ins. Wide ranges of software plug-ins are available from SigmaTel and from third-party partners, providing features such as bass response enhancement, spatial enhancement, and low latency filtering.

The STAC9221 and STAC9220 are intended to support the Dolby Laboratories PC Entertainment Experience program. The STAC9221 audio performance is targeted at the Dolby(R) Master Studio(TM) specifications and the STAC9220 is targeted at the Dolby(R) Home Theater(TM) specification.

"We're pleased to provide our customers with this next generation theater quality audio technology, along with the extensive software features of Intel(R) Audio Studio," says Joel Christensen, Director of Marketing, Intel Desktop Board Operations

For more information on SigmaTel products, as well as development information and sales support, please visit www.sigmatel.com.

About SigmaTel:

SigmaTel Inc. a fabless semiconductor company headquartered in Austin, Texas, designs, develops, and markets proprietary, analog intensive, mixed-signal ICs for a variety of products in the consumer electronics and computing markets, including portable compressed audio players, such as MP3 players, notebook and desktop PCs, DVD players, digital televisions, and set-top boxes. SigmaTel provides complete, system-level solutions that include highly integrated ICs, customizable firmware and software, software development tools, reference designs, and applications support. The Company's focus is on providing system-level solutions that enable customers to rapidly introduce and offer electronic products that are small, light-weight, power-efficient, reliable, and cost-effective. SigmaTel is ISO 9001:2000 certified and is committed to providing customers with high performance, quality products along with superior customer service.

Cautionary Language: This press release contains forward-looking statements based on current SigmaTel expectations. The words "expect," "will," "should," "would," "anticipate," "project," "outlook," "believe," "intend," and similar phrases as they relate to SigmaTel or future events are intended to identify such forward-looking statements. These forward-looking statements reflect the current views and assumptions of SigmaTel, but are subject to various risks and uncertainties that could cause actual results to differ materially from expectations. A number of important factors could cause actual results to differ materially from those in the forward-looking statements, and there will be events in the future that SigmaTel is not able to accurately predict or control. For a discussion of factors that could impact SigmaTel's financial results and cause actual results to differ materially from those in the forward-looking statements, please refer to recent SigmaTel filings with the SEC, particularly the 424(b)(4) final prospectuses filed September 19, 2003 and February 19, 2004, the Form 10-Qs that were filed on October 29, 2003, April 20, 2004, July 20, 2004 and October 19, 2004, the Form 10-K that was filed on February 17, 2004, and the Form 10-K that SigmaTel filed February 8, 2005 covering the annual period ended December 31, 2004.

Universal Jacks is a trademark and SigmaTel is a registered trademark of SigmaTel. All other products and brand names as they appear in this release are trademarks or registered trademarks of their respective holders. All specifications may be changed without notice.