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More MEMS Microphone Options

Everything’s going HD these days, and audio is no exception. That means that everything in the audio chain, from microphone to speaker, has to step up its game.

Akustica announced their first HD microphone in late 2012; they recently announced some new additions to the family.

And once again, packaging demonstrates that it refuses to be taken for granted with microphones. This is illustrated in two different aspects of the new Akustica offerings.

First is the notion of where the port goes. Port location makes a difference in the acoustics, but it also impacts designers that want more flexibility in locating and mounting the mics on very small boards like those inside phones. This is even truer given that multiple mics are becoming the rule for noise cancellation and other reasons.

So sometimes a designer wants to use a top-ported mic; sometimes a bottom-ported one. The thing is, apparently the audio software strongly prefers that the microphones be identical (or close to it). Changing the porting can screw that up, either resulting in tougher software or less placement flexibility for the designer.

So Akustica has announced matched top- and bottom-ported microphones. The idea is that you can use either one and they’ll still be close to “identical” (±1%). They accomplish the matching with a combination of tight manufacturing tolerances and a calibration step at test. Both the MEMS element itself and the accompanying ASIC are optimized.

The second package impact – and die strategy – has to do with the package size. With most every IC or sensor, smaller is always better (ignoring price). Not so with microphones. Given more space, you can do a two-die solution, optimizing MEMS and ASIC separately. You also have more cavity room in the package, which is important for sound quality.

So, while they’ve announced their matched high-performance HD mics, they also announced what they say is the smallest microphone around, in a 2×3 mm2 package. It is said to have good performance, but does compromise somewhat from the larger devices to achieve the smaller size.

You can read more about these in their announcement.

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