An integrated silicon capacitive microphone with frequency-modulated digital output

M. Pedersen, Wouter Olthuis, Piet Bergveld

    Research output: Contribution to journalArticleAcademicpeer-review

    16 Citations (Scopus)

    Abstract

    In this paper a new integrated capacitive silicon microphone with frequency-modulated digital output is described. The FM output can be processed directly by a digital system without the need of analog-to-digital conversion, which is normally required with capacitive microphones in digital systems. The integrated microphone comprises a polyimide structure fabricated directly on a silicon substrate, on which the oscillator has already been completed using a standard CMOS process. This is possible since the polyimide microphone process is fully IC-compatible. The capacitance of the microphone modulates the output frequency of the oscillator, and from experiments a sensitivity of 234 Hz/Pa is measured at a carrier frequency of 263 kHz. The frequency response is flat (±1 dB) within the measured range of 100 Hz to 15 kHz. The A-weighted noise is 4.5 Hz for a bandwidth of 15 kHz, yielding an equivalent noise level of the microphone of 60 dB(A) re. 20 μPa. The measurements have shown to be in good agreement with the theoretical models.
    Original languageUndefined
    Pages (from-to)267-275
    Number of pages9
    JournalSensors and actuators. A: Physical
    Volume1998
    Issue number69
    DOIs
    Publication statusPublished - 1998

    Keywords

    • METIS-111840
    • IR-73632
    • Silicon capacitive frequency modulated microphone

    Cite this

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    title = "An integrated silicon capacitive microphone with frequency-modulated digital output",
    abstract = "In this paper a new integrated capacitive silicon microphone with frequency-modulated digital output is described. The FM output can be processed directly by a digital system without the need of analog-to-digital conversion, which is normally required with capacitive microphones in digital systems. The integrated microphone comprises a polyimide structure fabricated directly on a silicon substrate, on which the oscillator has already been completed using a standard CMOS process. This is possible since the polyimide microphone process is fully IC-compatible. The capacitance of the microphone modulates the output frequency of the oscillator, and from experiments a sensitivity of 234 Hz/Pa is measured at a carrier frequency of 263 kHz. The frequency response is flat (±1 dB) within the measured range of 100 Hz to 15 kHz. The A-weighted noise is 4.5 Hz for a bandwidth of 15 kHz, yielding an equivalent noise level of the microphone of 60 dB(A) re. 20 μPa. The measurements have shown to be in good agreement with the theoretical models.",
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    author = "M. Pedersen and Wouter Olthuis and Piet Bergveld",
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    An integrated silicon capacitive microphone with frequency-modulated digital output. / Pedersen, M.; Olthuis, Wouter; Bergveld, Piet.

    In: Sensors and actuators. A: Physical, Vol. 1998, No. 69, 1998, p. 267-275.

    Research output: Contribution to journalArticleAcademicpeer-review

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    T1 - An integrated silicon capacitive microphone with frequency-modulated digital output

    AU - Pedersen, M.

    AU - Olthuis, Wouter

    AU - Bergveld, Piet

    PY - 1998

    Y1 - 1998

    N2 - In this paper a new integrated capacitive silicon microphone with frequency-modulated digital output is described. The FM output can be processed directly by a digital system without the need of analog-to-digital conversion, which is normally required with capacitive microphones in digital systems. The integrated microphone comprises a polyimide structure fabricated directly on a silicon substrate, on which the oscillator has already been completed using a standard CMOS process. This is possible since the polyimide microphone process is fully IC-compatible. The capacitance of the microphone modulates the output frequency of the oscillator, and from experiments a sensitivity of 234 Hz/Pa is measured at a carrier frequency of 263 kHz. The frequency response is flat (±1 dB) within the measured range of 100 Hz to 15 kHz. The A-weighted noise is 4.5 Hz for a bandwidth of 15 kHz, yielding an equivalent noise level of the microphone of 60 dB(A) re. 20 μPa. The measurements have shown to be in good agreement with the theoretical models.

    AB - In this paper a new integrated capacitive silicon microphone with frequency-modulated digital output is described. The FM output can be processed directly by a digital system without the need of analog-to-digital conversion, which is normally required with capacitive microphones in digital systems. The integrated microphone comprises a polyimide structure fabricated directly on a silicon substrate, on which the oscillator has already been completed using a standard CMOS process. This is possible since the polyimide microphone process is fully IC-compatible. The capacitance of the microphone modulates the output frequency of the oscillator, and from experiments a sensitivity of 234 Hz/Pa is measured at a carrier frequency of 263 kHz. The frequency response is flat (±1 dB) within the measured range of 100 Hz to 15 kHz. The A-weighted noise is 4.5 Hz for a bandwidth of 15 kHz, yielding an equivalent noise level of the microphone of 60 dB(A) re. 20 μPa. The measurements have shown to be in good agreement with the theoretical models.

    KW - METIS-111840

    KW - IR-73632

    KW - Silicon capacitive frequency modulated microphone

    U2 - 10.1016/S0924-4247(98)00092-2

    DO - 10.1016/S0924-4247(98)00092-2

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    SP - 267

    EP - 275

    JO - Sensors and actuators. A: Physical

    JF - Sensors and actuators. A: Physical

    SN - 0924-4247

    IS - 69

    ER -