Microphones use dual-backplate MEMS technology

14th March 2018

Mick Elliott

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Datasheet

The IM69D120 and IM69D130 XENSIV MEMS microphones from Infineon Technologies are available at Mouser Electronics. The high-performance, low-noise microphones are ideal for applications such as high-quality audio capture, voice user interface, active noise cancellation, or audio pattern detection in monitoring systems.

The microphones, are designed for applications that require low self-noise, wide dynamic range, low distortion and a high acoustic overload point.

They incorporate Infineon's dual-backplate microelectromechanical systems (MEMS) technology to enable high linearity of the output signal within a dynamic range of up to 105dB.

The dual-backplate MEMS technology is based on a miniaturised symmetrical microphone design, similar as utilised in studio condenser microphones, which generates a truly differential signal.

This allows improved high frequency immunity for better audio signal processing and increases the acoustic overload point of 10-percent total harmonic distortion (THD) to 135dB SPL.

The 4mm × 3mm microphones feature a noise floor of just 25dBA (69dBA signal-to-noise ratio (SNR)), with distortion less than 1%, even at sound pressure levels of 128dB SPL. For design agility, the IM69D120 microphone has been specifically designed to preserve the 69dBA SNR within the dynamic range of a 16-bit system, whereas the IM69D130 is ideal for 20-bit systems.

The SNR is an improvement of 5dB compared to a conventional MEMS microphone, essentially doubling the possible distance between a user and the device capturing a voice command.

Additionally, the microphones’ flat frequency response and tight manufacturing tolerance result in close phase matching of the microphones, benefiting microphone array applications.