MEMS microphone smoothes the way to natural voice control in smart consumer devices

October 21, 2011 // By Paul Buckley
STMicroelectronics has expanded the company’s sensor portfolio with a new high-performance, low-power digital MEMS microphone. Housed inside an ultra-small 3 x 4 x 1 mm package, ST’s MP34DT01 top-port microphone delivers a best-in-class audio experience in mobile phones, tablets and other smart consumer devices.

The MP34DT01 employs a patent-pending technology that allows designers to place the microphone membrane closer to the acoustic port hole on the top of the package with a substantial increase in performance and no penalty in size. It is the first MEMS microphone in the market that couples the advantage of a top-port sound-inlet position with unparalleled signal-to-noise ratio (SNR) of 63 dB and flat frequency response in the full audio band of 20–20,000 Hz.
ST’s MP34DT01 outclasses competing devices as the first top-port digital MEMS microphone with better acoustic parameters than existing bottom-port mics. The device perfectly matches the needs of clever speech-recognition systems for voice-controlled software and electronic-assistant applications being used in new consumer applications, where improving audio intelligibility without increasing the workload on the main processor, is a key factor. The device’s best-in-class SNR makes it also suitable for applications beyond typical consumer applications, such as phonometers – sound-level meters that require high dynamic range.ST’s MEMS microphones use best-in-class acoustic sensor technology jointly developed with OMRON that is inherently less susceptible to mechanical vibration, temperature variations and electromagnetic interference, while providing high-fidelity reproduction of audio signals at low power consumption.
In addition to the size, robustness and low-power advantages compared with traditional condenser microphones, MEMS microphones enable dramatic advancements in sound quality in multiple-microphone applications. Such microphone arrays, facilitated by the small form factor, superior sensitivity matching and frequency response of ST’s microphones, enable the implementation of active noise and echo cancelling, as well as beam-forming, a sound-processing technology that helps isolate a sound and its location. These features are invaluable with the increasing use of cell phones and other devices in noisy and uncontrollable environments.

ST’s MEMS microphones pair perfectly with the latest generation of the Company’s Sound Terminal audio processing chips that feature a dedicated built-in interface for direct connection of a MEMS microphone, saving parts count and cost.
The MP34DT01 is