MEMS mics’ size, cost, audio performance fit array apps

MEMS mics’ size, cost, audio performance fit array apps

Combining true audio sound quality, small size, and low cost, the MP34DB01 and MP45DT02 digital MEMS microphones enable enhanced, multiple-mic audio designs for mobile phones, portable computers, tablets, gaming, and other voice-input applications. The microphones, which integrate the manufacturer’s electronic control circuit and an OMRON MEMS sensor in a single package, are said to be inherently less susceptible to mechanical vibration, temperature variations, and electromagnetic interference.

The MP34DB01 delivers flat frequency response from 20 to 20,000 Hz, has an SNR of 62 dB, and power-supply noise rejection of 70 dB — specifications that its manufacturer says make it the only device in the market with true high-fidelity audio response. Housed in a 3 x 4 x 1-mm package, the mic was been specifically designed for mobile phones, with the acoustic port hole placed on the bottom of the package. This layout enables phone manufacturers to mount it on the backside of the phone’s pc board, permitting slimmer designs while still providing a short acoustic path from environment to microphone.

The 3.76 x 4.72 x 1.25-mm MP45DT02 has a top sound port to meet the size and sound-inlet position requirements of laptops and tablets. It too provides solid frequency response, with a 58-dB SNR.

Both mics provide a PDM output that can be selected as left or right audio, and are well suited for use in multiple-microphone arrays, not only by their size and frequency response, but also their consistently matched sensitivity. Their performance not only enables use of active noise and echo cancelling, but also beam forming to help isolate a sound based on its location. The microphones’ high-temperature stability after reflow ensures flexibility in pc-board placement, including in locations with higher temperature excursions. ($1.40 ea / 1,000 — MP34DB01, available now in prod qty; MP45DT02, samples available now, prod qty 2nd qtr.)

By Richard Comerford

STMicroelectronics , Lexington , MA
Information 781-861-2650
www.st.com