ST's MEMS mic smoothes way to natural voice control in smart consumer devices

GENEVA, SWITZERLAND: STMicroelectronics has expanded its sensor portfolio with a new high-performance, low-power digital MEMS microphone. Housed inside an ultra-small 3x4x1 mm package, ST's MP34DT01 top-port microphone delivers a best-in-class audio experience in mobile phones, tablets and other smart consumer devices.

A technology breakthrough, 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. This 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 over 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 its Sound Terminal audio processing chips that feature a dedicated built-in interface for direct connection of a MEMS microphone, saving parts count and cost.

According to IHS iSuppli, the market for MEMS microphones for consumer electronics and mobile handsets is forecast to grow revenue at a CAGR of 23 percent between 2010 and 2014. The driving factors include the breakthrough in the use of noise suppression requiring multiple microphones, as well as adoption in new consumer applications beyond handsets and laptops, such as slate tablets and gaming.

The MP34DT01 is the second member in ST's high-end MEMS microphone family and new devices with best-in-class SNR and trimmable sensitivity for matching within 1dB, coupled with further size reduction, are in the pipeline for 2012 and 2013.
Already qualified by a top-tier cell-phone maker, ST's top-port MP34DT01 MEMS microphone is available in mass production, with unit pricing $1.42 in quantities of 1,000 pieces.