Boffins tout world's first single-chip digital microphone

Akustica develops MEMS-on-standard-CMOS process

US start-up Akustica today launched what it claims is the world's first micro-mechanical digital microphone chip that can be manufactured using standard chip-making processes. Pitching the part primarily at PCs, the company said the new part is sufficiently inexpensive to make microphone arrays in notebook screens and desktop monitors commonplace.

akustica aku2000 digital microphone chip

Most of the microphones integrated into PCs, mobile phones, PDAs, Bluetooth headsets and the like are made using the traditional analogue coil-and-magnet technique or capacitors. Digital-output versions - so-called microelectromechanical systems (MEMS) - made using the same lithography processes used to design CPUs, GPUs and memory but with microscopic moving parts, are becoming more common. However, since they're made using customised fabrication processes, they're expensive.

But not so for Akustica's AKU2000 chip, company co-founder and CTO Ken Gabriel said. It's made using a standard CMOS process, allowing the company to leverage almost any fab or foundry in the world. Gabriel also contrasted the product with other MEMS microphone products which contain two chips wired together. The second chip contains signal processing circuitry of a kind built into Akustica's single-chip microphone, he said. And the 4 x 4mm one-chip product is easier to integrate into, say, a notebook screen's bevel.

Two or more AKU2000s brought together have, thanks to their single-chip approach and standard fabrication, more closely matched audio characteristics, Gabriel said, making them more suitable for array set-ups than existing products.

Why an array of microphones? Multiple inputs can be used to help cancel or at least significantly reduce background noise and improve the quality of the source. Intel has been touting microphone arrays for notebooks since it began developing its HD Audio specification. With the growth of interest in VoIP, both chip makers believe adding multiple microphones will be key to improving the quality of VoIP calls, especially those made on the move.

Akustica also has its eye on mobile phone and Bluetooth headset applications, both of which can benefit from the noise-reduction capabilities of multiple, cheap microphones, company marketing chief Davin Yuknis said.

The AKU2000 is sampling now and is priced at $3.87 per unit in 1000-piece quantities. ®

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