INMP441 MEMS High-Precision Omnidirectional Microphone – Digital I2S Interface Module for ESP32, STM32, and Raspberry Pi

Product Description The INMP441 is a high-performance, low-power, digital-output omnidirectional MEMS microphone with a bottom port. It is specifically designed for applications requiring high-fidelity audio capture and digital signal processing. Unlike traditional analog microphones, the INMP441 features an integrated I2S (Inter-IC Sound) interface, which outputs a 24-bit pulse code modulated (PCM) signal directly to your microcontroller. This eliminates the need for an external analog-to-digital converter (ADC) or a pre-amplifier, drastically reducing signal noise and interference. It is the gold standard for voice recognition, smart assistants, and IoT audio logging projects using modern 3.3V platforms like ESP32, STM32, and Raspberry Pi.

Key Features

• Digital I2S Interface: Provides direct digital audio streaming to microcontrollers, ensuring zero loss in signal quality during transmission.

• Omnidirectional Pickup: Uniformly picks up sound from all directions, making it ideal for room-scale voice monitoring and environmental sensing.

• Ultra-Low Power Consumption: Draws only 1.4mA during active operation, perfect for battery-powered wearable devices and wireless nodes.

• High Signal-to-Noise Ratio (SNR): Boasts a 61 dBA SNR for clear, crisp audio even in complex environments.

• Flat Frequency Response: Provides a natural sound profile from 60 Hz to 15 kHz,

Technical Details

• MEMS Architecture: Utilizes a highly stable silicon-diaphragm MEMS element for consistent performance across varied temperatures.

• Digital 24-bit Output: Provides high-resolution audio data, allowing for advanced digital filtering and machine learning applications.

• Bottom Port Design: The acoustic port is located on the underside of the PCB for improved acoustic sealing in enclosure designs.

• Clock Synchronization: Requires a Bit Clock (SCK) and Word Select (WS) signal provided by the I2S master device.

• Left/Right Selection: Features a dedicated L/R pin to configure the microphone as the left or right channel in a stereo pair.

• Logic Voltage Range: Optimized for 1.8V to 3.3V systems; standard ESP32 3.3V rails are perfectly compatible.

• Power Supply Rejection (PSR): Excellent PSR of -75 dBFS minimizes the impact of power supply ripples on audio quality.

• Sampling Flexibility: Supports a wide range of sample rates, typically from 8 kHz up to 48 kHz for CD-quality recording.

• Compact Footprint: Miniature PCB design with high-quality gold-plated pads for low-impedance electrical connections.

• Integrated Hardware Filter: Includes a built-in high-pass filter to eliminate low-frequency "thumping" or mechanical vibration noise.

• Lead-Free Construction: Fully RoHS compliant, ensuring environmental safety for commercial product integration.

• Sleep Mode: Automatically enters low-power standby when clock signals are disabled by the master microcontroller.

• Signal Polarity: Consistent phase response, essential for beam-forming microphone arrays and noise-cancellation projects.

• Dynamic Range: High acoustic overload point (AOP) allows it to capture loud sounds without clipping.

• Pin Configuration: SCK (Clock), SD (Data), WS (Word Select), L/R (Channel Select), VCC, and GND.