By Cameron Chai
STMicroelectronics has unveiled two digital MEMS microphones. The MP34DB01 and MP45DT02 devices that combine enhanced sound quality and toughness in a cost effective and nano-scale package to offer increased audio capability in mobile phones, portable computers and applications featuring a voice input.
Market analyst, iSuppli predicts that the MEMS microphones revenue for consumer electronics and mobile handsets will grow at a CAGR of 24% over the period 2009 to 2014. Factors that will impact this growth include the application of noise suppression that will necessitate multiple microphones, in s applications in new consumer products including slate tablets and gaming.
The devices utilize acoustic sensor technology developed in collaboration with OMRON(2) that resists mechanical vibration, temperature fluctuations and electromagnetic disturbance, and reproduce audio signals accurately. It incorporates an electronic control circuit and OMRON's micro-machined sensor in one energy efficient package. This enhances battery life in portable systems.
The devices allow enhanced sound quality with multiple microphones in one device .These microphones facilitated by the nanosize, enhanced sensitivity and frequency response, ensure the use of active noise and echo canceling and beam-forming. Beam-forming is a sound-processing technology that enables identifying a sound and its location.
The high temperature stability of the devices following reflow allows for flexibility in microphones placement, in areas with temperature fluctuations. The MP34DB01 delivers high-fidelity audio bandwidth, with flat frequency reaction in the full audio band of 20 to 20,000Hz, along with a signal-to-noise ratio of 62 dB and power-supply noise rejection of 70 dB.
The device is encased in a 3x4x1mm package ideal for mobile phones, where the acoustic port hole is placed at the bottom of the package. This design helps phone developers to place the microphone behind the cell-phone printed circuit board to deliver slim designs with a short external sound path to the microphone.
The MP45DT02 is a top-port 3.76x4.72x1.25mm product suitable for laptops and tablets. It offers signal-to-noise ratio (58 dB) and enhanced frequency response. The devices couple with the Sound Terminal audio processing chips that have an in-built interface that allows the device to be directly connected, reducing component count and cost.