SigmaTel Acquires Industry Leading DDX(R) Digital Amplifier Technology; Company Continues Product and Market Diversification with Addition of Digital Amplifier Technology.

AUSTIN, Texas -- SigmaTel, Inc. (NASDAQ:SGTL), a leader in mixed-signal multimedia semiconductors, today announced it has acquired the Direct Digital Amplification (DDX(R)) technology, design team and intellectual property from Apogee Technology, Inc. (AMEX:ATA). DDX Technology is a high efficiency, Class-D digital amplifier technology that converts digital audio directly into power without the need of a digital to analog conversion (DAC). The technology is an all digital solution that has a higher efficiency level allowing for smaller form factor designs and lower power dissipation than the average analog solution. The technology is currently embodied in several patented all-digital, high efficiency ICs which are used in a wide range of consumer audio products.

DDX technology is a natural extension of the SigmaTel product family and extends SigmaTel's leadership in the high definition PC audio and consumer audio markets. The combination of SigmaTel's High Definition Audio codecs and the DDX technology will allow SigmaTel to continue to diversify its business and deliver customers increased integration and lower overall system costs. SigmaTel plans to integrate the DDX amplifier technology into current and future audio codecs which will allow smaller form factors, longer battery life, and lower bill of material (BOM) costs to consumer electronics manufacturers.

"SigmaTel continues to look at opportunities to diversify its business and integrate greater functionality into its product family allowing our customers to offer products they couldn't deliver before at a lower cost," said Ron Edgerton, SigmaTel's president and CEO. "The acquisition of the DDX technology allows SigmaTel to offer its customers a more powerful and robust high definition audio solution that can be designed into future consumer audio products."

STMicroelectronics currently licenses and sells Apogee's DDX technology based products. Companies that currently use DDX technology from either STMicroelectronics or Apogee, include Microsoft, Sony, Fujitsu, Kenwood, Sharp, RCA, Harmon Kardon, LG, Toshiba, JBL, Magnavox, Hitachi and Philips.

Through the acquisition, SigmaTel will acquire six patents and patent applications, as well as an engineering and sales team located in the Boston area and in Asia. The DDX technology engineering team consists of digital and analog IC designers, product application and software engineers. Apogee will retain all non-DDX related assets and personnel.

SigmaTel has paid an undisclosed sum of cash as consideration for the acquisition. The terms of the transaction include a contingent earn-out payment based upon revenues of the business for the one-year period following the acquisition. SigmaTel expects to record a one-time charge for purchased in-process research and development expenses related to the acquisition in its fourth quarter, ending December 31, 2005. The amount of that charge, if any, has not yet been determined.

For more information on SigmaTel, please visit www.sigmatel.com. For more information on Apogee Technology, Inc., please visit www.apogeeddx.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 digital multimedia products in the consumer electronics and computing markets, including portable compressed audio players, such as MP3 players, notebook and desktop PCs, digital video cameras, multi-function peripheral products, 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 Form 10-K that was filed on February 8, 2005 and the Form 10-Q that was filed on August 9, 2005.

SigmaTel is a registered trademark of SigmaTel, Inc. 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.