Infineon has launched a microphone based on micro-machined silicon technology that will directly challenge US startup Akustica, which holds some fundamental patents licensed from Carnegie Mellon university. The startup recently saw its parts shipping in laptops from Fujitsu and a deal with Ricoh, but with Infineon now in the market with strong links to automotive manufacturers and high volume manufacturing, the smaller company may struggle. Unless of course it goes for the legal route, and the Akustica management are convinced they have a fundamental position.
The Infineon Silicon Microphone consists of two chips combined in a single package. The MEMS chip is a capacitor made up of a stiff and perforated backplate and a flexible membrane on a silicon substrate and transfers the sound waves into capacity variations. The ASIC chip converts the capacity variations into an electrical signal.
The new silicon MEMS microphone that is much more heat-resistant and rugged than the typical microphones used today, which are based on electret condenser microphone (ECM) technology. The silicon MEMS microphone can withstand temperatures of up to 260 C and is much more immune to vibrations and shocks, so it can be easily soldered onto any standard PCB and is ideally suited to use on fully automated production lines common to mass market consumer products. A 1.5 to 3.3V power supply slashes the miniature microphone's power consumption to about one third (70 µA) that of ECM microphones.
Silicon MEMS microphones can be used in anything from new mobile handset and headset models, to consumer electronics and notebook applications, medical systems, such as hearing aids, and even for such automotive applications as hands-free phones. Several identical individual microphones can easily be configured to form the arrays for directional microphones, as the conformance of silicon microphones can be ensured and variations over time remain low.
“We can even envision using these microphones in industrial applications as acoustic sensors to monitor machinery for example,” says Peter Schiefer, head of the Discrete Semiconductors business unit at the Automotive, Industrial and Multimarket business group of Infineon Technologies.Market researcher firm Wicht Technology Consulting (WTC) estimates that the market for silicon microphones will grow from $56m in 2005 to $680m in 2010.
The microphone has a signal-to-noise ratio (59dB(A)) and high sensitivity (10mV/Pa).