Monday, May 22, 2006
High-end laptop computers are switching from analog to digital microphones based on microelectromechanical systems, according to Akustica Inc. (Pittsburgh), which announced its first design win Monday (May 22).
Fujitsu's LifeBook Q2010 will include two AKU2000 single-chip microphones located on the display's bezel. Akustica also announced a new chip model, the AKU2001, which permits multiple microphones to share a single interface wire. SigmaTel Inc. (Austin, Texas), the coder/decoder maker, simultaneously announced specific support for AKU2001 microphones, permitting designs to multiplex microphones on a single interface wire with no additional circuitry.
"Fujitsu is just our first customer adoption annoucement, but we have many other design wins pending," said Davin Yuknis, vice president of marketing at Akustica.
Yole Development (Lyon, France) claims that the silicon microphone market reached nearly 100 million units last year and will grow to 800 million units by 2010. Most are analog silicon chip microphones made for analog cellphones by Knowles Electronics (Itasca, Ill.) and Sonion MEMs A/S (Roskilde, Denmark).
In contrast, Akustica's silicon microphone includes an analog-to-digital converter on the same chip, simplifying integration into notebook PCs and other digital devices.
The partners used MEMS techniques to fabricate an ultra-tiny microphone diaphragm. However, Akustica's diaphragm was fabricated on a standard CMOS wafer along with all supporting circuitry. The diaphragm is freed to move by a second step that etches away sacrificial material below and around it. Akustica claimed its design simplifies system designs by combining the diaphragm, analog preamplifier and A/D converter functions on the same CMOS chip, thereby simplifying integration with digital devices like the expanding number of voice-over-Internet-protocol (VoIP) ports.
SigmaTel separately unveiled a family of four-channel high-definition audio codec chips. SigmaTel's new STAC9205 and STAC9255 codecs can handle two AKU2001 microphones on a single interface wire. The four-channel codecs allow two-channel VoIP to run simultaneously with other two-channel stereo audio applications.
The on-chip interface allows notebook manufacturers to handle two-channel, high-definition audio applications or integrate up to four digital microphones for future stereo signal localization and noise cancelling algorithms built into Microsoft's forthcoming Vista operating system.
By: DocMemory
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