The INMP421 is a low cost, low power, digital output bottom ported omnidirectional 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 two 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 sound with 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 is 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.