Knowles Acoustics (Itasca, Ill.) has shipped its one billionth micro-electro-mechanical system (MEMS) microphone, which the company claims makes it the world's largest supplier. Sales of its surface-mount SiSonic MEMS microphone has catapulted Knowles Acoustics into the top MEMS microphone slot as well as placed it in the top five MEMS suppliers for consumer and mobile applications, according to iSuppli Corp. (El Segundo, Calif.) Knowles Acoustics, a supplier of traditional electret microphones, delivered its first MEMS microphone in 2003, two years behind the debut of the world's first MEMS microphone by Akustica Inc. (Pittsburgh). Since then Knowles Acoustics has become the world's largest supplier of MEMS microphones, passing by Akustica who claims to have delivered only five million microphones to date. Akustica was recently acquired by Robert Bosch North America. Knowles manufactures its SiSonic MEMS microphones in its own dedicated 80,000 square foot fab in Suzhou, China, where it currently makes 30 different models of MEMS microphones, which it supplies to makes of mobile phones, laptop computers, gaming systems, and Bluetooth headsets.