November 13, 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

About TDK Corporation

TDK Corporation is a leading electronics company based in Tokyo, Japan. It was established in 1935 to commercialize ferrite, a key material in electronic and magnetic products. TDK's portfolio includes electronic components, modules and systems marketed under the product brands TDK and EPCOS, power supplies, magnetic application products as well as energy devices, flash memory application devices, and others. TDK focuses on demanding markets in the areas of information and communication technology and consumer, automotive and industrial electronics. The company has a network of design and manufacturing locations and sales offices in Asia, Europe, and in North and South America. In fiscal 2012, TDK posted total sales of USD 9.9 billion and employed about 79,000 people worldwide.

About TDK-EPC Corporation

TDK-EPC Corporation, a TDK group company, is the manufacturer of TDK’s electronic components, modules and systems and is headquartered in Tokyo, Japan. TDK-EPC was founded on October 1, 2009, from the combination of the electronic components business of TDK and the EPCOS Group. The product portfolio includes ceramic, aluminum electrolytic and film capacitors, ferrites, inductors, high-frequency components such as surface acoustic wave (SAW) filter products and modules, piezo and protection components, and sensors.

For further information on this product contact EPCOS Sales at

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