PORTLAND, Ore -- Micro-electro-mechanical systems (MEMS) microphones have become so much more than smaller versions of the once ubiquitous electrostatic induction based microphones -- electrets -- before them.
MEMS microphones are enabling a whole new tier of "always on" connected, handheld and wearable electronics that will eventually monitor not just our every sound but also those in the environment around us. As such, our devices will not only interpret our voice commands, hand gestures and even the emotions in our voice patterns, but will begin to anticipate our needs by listening to the activity around us and volunteering the information we need at the exact moment we need it.
Once portrayed as a dead-end market destined to become a mere commodity where the most important parameter was cost. Today MEMS microphones have proven that their added value has no bound in sight.
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There are over a dozen suppliers of MEMS microphones worldwide, according to the latest IHS report MEMS and Sensors Report, Microphones 2014 -- with Knowles far ahead of the second-tier suppliers -- many of which are getting their die from Infineon, Omron or MEMSense. Note Akustica is owned by Bosch and Invensense bought Analog Devices MEMS microphone business in 2013. Click here for larger image
MEMS microphone makers worldwide are cashing in on a market that will top $1 billion in sales in 2014 according to IHS Inc. (Englewood, Colo.). The majority of the die inside these MEMS microphones come from just a few suppliers:
Knowles Corp. (Itasca, Ill.) makes its own dies;
Infineon Technologies AG (Neubiberg, Germany) supplies dies to AAC Technologies Holdings Inc. (Shenzhen, China), Goertek Inc. (Shandong, China), Best Sound Electronics, BSE Co. Ltd. (Seoul, Korea), Hosiden Corp. (Osaka, Japan), Gettop Acoustic Co. Ltd. (ShanDong, China) and others;
Invensense Inc. (San Jose, Calif.), who bought Analog Devices unique single-chip CMOS MEMS microphone business in 2013, uses TSMC foundry;
While always using its own interface device STMicroelectronics (Geneva, Switzerland) sources the mechanical chip for some of its MEMS microphones from Omron Corp. (Kyoto, Japan);
A handful of others also make their own proprietary MEMS microphone dies, notably Akustica (manufactured by parent company Robert Bosch GmbH, Stuttgart, Germany), Wolfson Microelectronics pic, Edinburgh U.K. (acquired by Cirrus Logic, Inc., Austin, Texas) is believed by IHS to be using a Teledyne Dalsa Inc. (Waterloo, Canada) foundry;
and several Chinese and Japanese manufacturers are making MEMS microphone die, such as MEMSensing Microsystems Co., Ltd. (Suzhou, China) and New Japan Radio Co. (NJRC, Tokyo).
Beside smartphones, tablets all use MEMS microphones, also many PCs are switching over because they can locate mutiple MEMS in the bezel for noise cancelling and beam stearing. Apple's smart watch due this fall will use MEMS microphones also video camera, still cameras and digital recorders are all moving to MEMS mics. For the next generation, wearables will use MEMS mics and portable medical devices and the list goes on.
You are right many applications of MEMS Mic array are under development in many different areas, in the filed of mechanical engineering, environmental science, medical electronics etc. Soon many products will be in the market using MEMS Mic arrays. Although these Mics are still not being tried as conventional microphones that are used in live performances.
Your are right too. Even though there are MEMS mics with HD quality, here is the breakdown on where they are used today (according to IHS)-- mobile phones (70 percent), tablets (13 percent), MEMS mics in headphones that manufacturers supply with their smarphones (9 percent), laptops (6 percent) and wearables (2 percent).
Oh that's an answer with fact figures; my estimation was based on the observation of my own. But yes it is very true that MEMS Mics will be having more chances of acceptance in other left out application with possible use of it for betterment.
It would be interesting to know how far digital microphones (DMICs) -- MEMS mics that include the A/D converter -- have penetrated within the overall MEMS mic market. From an interface perspective, integrating the A/D into the same package as the MEMS makes so much more sense -- especially for applications requiring many microphones (beam-forming arrays, etc.). From the perspective of the audio processor at the receiving end, the two-wire PDM data & clock interface from a DMIC is so much easier to handle than a low-level analog signal, that it's probably well worth the extra cost of the MEMS mics with built-in A/D converters.
All your arguements for digital outputs are valid, and in fact the first startup's first microphone (Akustica) had digital outputs. Unfortunately, its kind of like the VHS versus Beta video take war--if you can remember that far back--everybody was already set up for analog mics (electrets) so much so that even Akustica has had to acquiesce a prodeuce analog models. But I am with you, and think hat eventually all MEMS mics will be digital.
In January Harman announced unidirectional analog and digital MEMS microphones with SNR (signal-to-noise ratio) up to 68 dBA. Have you come across anyone designing these in yet? If a single MEMS microphone can replace multi-mic arrays for noise cancelation, it should speed adoption by significantly reducing the cost and space required within the target device. Thoughts?
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