November 2012

Acoustic components

Top-port MEMS microphones with flat frequency response

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TDK Corporation presents the two new EPCOS C920 and C923 MEMS microphones. With footprints of only 2.75 x 1.85 mm² each and an insertion height of 0.9 mm, they are among the smallest top-port microphones worldwide. Thanks to their low insertion height and their design, the air volume in the microphones is small, so that no resonances occur in the 10 kHz range. This results in outstanding audio quality with a flat frequency response.

In addition to this, the new MEMS microphones have a very good signal-to-noise ratio of 56 dB (C920) and 57 dB (C923) respectively. The C923 type offers a very flat frequency response even in the lowest frequency range of the audio spectrum. A high-pass filter that suppresses frequencies below 100 Hz is integrated into the C920 microphone. This means that no wind noise is transmitted, for instance.

At supply voltages of between 1.64 and 3.6 V DC, the current consumption is only 125 µA. These RoHS-compatible components have an output impedance of 260 Ω.


  • Top-port microphone: In this design, the acoustic opening is located on the upper side of the component

Main applications

  • Smartphones and conventional mobile phones

Main features and benefits

  • No resonance thanks to low air volume
  • Outstanding audio quality with a flat frequency response



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