INMP421: Omnidirectional Microphone with Bottom Port and PDM Digital Output


InvenSense MEMS Microphone

The INMP421 is a low cost, low power, digital output bottom ported omni-directional MEMs microphone. The ADM421 consists of a MEMs microphone element, an output amplifier and a 4th order sigma delta modulator. The digital interface allows for the PDM (Pulse Density Modulated) output of to microphones to be time multiplexed on a single data line using a single clock.

The INMP421 has a high SNR and a high sensitivity making it an excellent choice for far field applications. The INMP421 has a flat wideband frequency response resulting in natural soundwith high intelligibility. Low current consumption and a sleep mode enable long battery life for portable applications. The INMP421 complies with the TIA-920 Telecommunications Telephone Terminal Equipment Transmission Requirements for Wideband Digital Wireline Telephones standard.

The INMP421 will be available in a very thin 3 mm × 4 mm × 1 mm surface mount package. It is reflow solder compatible with no sensitivity degradation. It is halide-free.

† – 7” Tape and reel to be discontinued. Contact for availability.

INMP421 Functional Block Diagram

INMP421 Functional Block Diagram


  • Feature Phones
  • Tablet Computers
  • Teleconferencing Systems
  • Digital Still and Video Cameras
  • Bluetooth Headsets
  • Notebook PCs
  • Security and Surveillance

Features and Benefits

  • Small and thin 3 mm × 4 mm × 1 mm surface mount package
  • SNR 61 dBA
  • High Sensitivity -26 dBFS
  • Flat Frequency Response from 100 to 15 kHz
  • Low Current Consumption < 650 μAmps
  • High PSRR of 80 dBFS
  • 4th Order Sigma Delta Modulator
  • Digital PDM output
  • Compatible with Sn/Pb and Pb-free solder processes
  • RoHS/WEEE compliant


Application Notes (General)

Application Notes (Specific)

Evaluation Board User Guides


Part # Output Port Location SNR Equivalent
Input Noise
Frequency Response
Maximum SPL Sensitivity @1kHz Sensitivity Tol Package Size Documentation Flex Board Evaluation Board Device
UNITS: (dBA) (dBA) (min - max) +/- dB mm (.pdf) (add to cart) (add to cart) (add to cart)

PDM Bottom 61dB 33dB 100Hz - 15kHz 120dB SPL -26 dBFS 3dB 3.00x4.00x1.00 Datasheet

  • Disclaimer

    • InvenSense sensors should not be used or sold in the development, storing, production and utilization of any conventional or mass-destructive weapons or any other weapons or life-threatening applications as well as in any other life-critical applications including but not limited to medical equipment, transportation, aerospace and nuclear instruments, undersea equipment, power plant equipment, disaster prevention and crime prevention equipment. In devices or systems whereby malfunction of these products can be expected to result in personal injury and casualties, InvenSense customers using or selling these products do so at their own risk and agree to keep InvenSense harmless from any consequences. InvenSense reserves the right to make changes to this product, including its circuits and software, in order to improve its design and/or performance, without prior notice. InvenSense makes no warranty, either expressed or implied with respect to any product, and specifically disclaims all other warranties, including warranties for merchantability, non-infringement, and fitness for any particular purpose. For more information go to Terms and Conditions.

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