Overview
The INMP441 is a high-performance, low-power, digital-output omnidirectional MEMS microphone manufactured by InvenSense (a TDK Group Company). It combines a MEMS sensor element, signal conditioning, an analog-to-digital converter, and a 24-bit I2S (Inter-IC Sound) digital interface into a single compact package.
Because it outputs 24-bit digital audio directly over I2S (avoiding analog noise pick-up and ADC conversion losses), it is standard in ESP32 voice assistant projects (ESPHome, Alexa/Google Home DIY), smart speakers, noise monitors, and speech recognition applications.
Quick reference
Operating Voltage (VDD) | 1.8 V to 3.3 V DC (3.3 V nominal) |
| Interface | I2S Digital Bus (SCK / Bit Clock, WS / Word Select, SD / Data) |
| Directional Pattern | Omnidirectional |
| Sensitivity | -26 dBFS at 1 kHz, 94 dB SPL |
| Signal-to-Noise Ratio (SNR) | 61 dBA |
| Frequency Response | 60 Hz to 15,000 Hz |
| Max Acoustic Input | 120 dB SPL |
Channel Select (L/R) | LOW = Left channel data, HIGH = Right channel data |
| Operating Current | 1.4 mA active, 17 µA sleep mode |
Pinout
Standard 6-Pin Breakout Header
| Pin | Name | Type | Description |
|---|---|---|---|
| 1 | VDD | Power | Supply voltage (+1.8 V to +3.6 V DC, 3.3V recommended) |
| 2 | GND | Power | Ground (0 V) |
| 3 | SD | Digital Output | I2S Serial Data output line |
| 4 | L/R | Digital Input | Left/Right Channel Select (LOW = Left channel, HIGH = Right channel) |
| 5 | WS | Digital Input | I2S Word Select / Frame Clock line (LRCK) |
| 6 | SCK | Digital Input | I2S Serial Bit Clock line (BCLK) |
Specifications
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions |
|---|---|---|---|---|---|---|
| Supply Voltage | 1.8 | 3.3 | 3.6 | V | DC | |
| Supply Current | — | 1.4 | 2.2 | mA | , active mode | |
| Standby Current | — | 17 | 50 | µA | Clock stopped | |
| Sensitivity | -29 | -26 | -23 | dBFS | 1 kHz, 94 dB SPL | |
| Signal-to-Noise Ratio | — | 61 | — | dBA | 20 kHz bandwidth, A-weighted | |
| Total Harmonic Distortion | — | 0.2 | 1.0 | % | 94 dB SPL, 1 kHz | |
| Dynamic Range | — | 87 | — | dB | Max SPL to noise floor |
I2S Timing & Channel Selection
The INMP441 streams 24-bit 2's-complement digital audio samples MSB-first:
L/RPin tied toGND: Microphone transmits 24-bit data during the Left channel period (WS= LOW). Data lineSDgoes high-impedance (tri-state) during the Right channel period (WS= HIGH).L/RPin tied toVDD: Microphone transmits 24-bit data during the Right channel period (WS= HIGH).- Stereo Configuration: Connect two INMP441 modules to the same I2S bus (
SCK,WS, andSDshared). SetL/R = GNDon Microphone 1 andL/R = VDDon Microphone 2.
Wiring
| INMP441 Pin | → | ESP32 Board (Example I2S Pinout) | Notes |
|---|---|---|---|
VDD | 3.3V | Must be 3.3V supply | |
GND | GND | Ground | |
L/R | GND | Selects Left Channel | |
SD | GPIO35 (or I2S DIN pin) | Serial Data Out | |
WS | GPIO25 (or I2S LRCK pin) | Word Select Clock | |
SCK | GPIO32 (or I2S BCLK pin) | Bit Clock Input |
Warning
Power Supply Voltage Limit & Bottom Port Hole:
- 3.3V Only: Supplying 5V directly to
VDDwill destroy the INMP441 MEMS IC. - Acoustic Port Obstruction: The MEMS sound port hole is located on the bottom of the PCB package. Do NOT block or place tape over the small hole on the underside of the breakout board!
Common mistakes
- Powering with 5V: Exceeding 3.6V damages the internal I2S ADC circuit.
- Floating
L/Rpin: LeavingL/Rdisconnected causes channel output ambiguity and silent audio buffers. - Using 8-bit or 10-bit ADC code: The INMP441 outputs 24-bit I2S data. Microcontroller software must configure the I2S peripheral for 24-bit or 32-bit sample resolution (with 24-bit data shifted into a 32-bit integer).
Notes
- Ideal for ESP-ADF, ESPHome
i2s_audiocomponent, and speech-to-text engines (Kaldi, Whisper, Rhasspy).
Assets & downloads
- datasheetdatasheet
- product-pagereference