Packaged MEMS microphones offer 70dB signal-to-noise ratio

28th July 2017

Alice Matthews

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Addressing the needs for high performance, low noise MEMS microphones, Infineon Technologies is entering the packaged silicon microphone market. The analogue and digital microphones are based on Infineon’s dual backplate MEMS technology and feature a 70dB signal-to-noise ratio (SNR). This is combined with a low distortion level of ten percent at a 135dB sound pressure level (SPL). In a 4x3x1.2mm MEMS package, the microphones are suited for high-quality acoustic recordings and far field voice capturing applications.

“This is an expansion of the established high volume bare die MEMS and ASIC business model with our packaging partners around the world,” said Dr. Roland Helm, Senior Director and Head of Product Line Sensors for Infineon’s Power Management and Multimarket Division. “We will continue to strengthen and grow our business with our partners with bare dies; additionally we now address low noise high-end use cases with our two new packaged microphones.”

Current MEMS microphone technology uses a sound wave actuated membrane and a static backplate. Infineon’s dual backplate MEMS technology uses a membrane embedded within two backplates thus generating a truly differential signal. This allows improved high frequency immunity for better audio signal processing and increases the acoustic overload point of ten percent Total Harmonic Distortion (THD) to 135 dB SPL.

The SNR of 70dB is an improvement of 6dB compared to a conventional MEMS microphone. This improvement is equivalent to doubling the distance from which a user can give a voice command that is captured by the microphone. Additionally, the analogue and digital microphones have excellent microphone-to-microphone matching (±1dB sensitivity matching and ±2° phase matching) which is suitable for implementing in arrays. For this reason the MEMS microphones are a suitable fit for ultra-precise beam forming and noise cancelling.