The **INMP411ACEZ-R0** is a high-performance, high-SPL (Sound Pressure Level), analog-output bottom-port MEMS microphone. It is designed by TDK InvenSense to handle loud environments without distortion while maintaining a small footprint. --- ### ## Technical Specifications Below are the primary electrical and performance characteristics of the component: | Parameter | Specification | | :--- | :--- | | **Output Type** | Analog (Single-Ended) | | **Directionality** | Omnidirectional | | **Sensitivity** | -46 dBV | | **Signal-to-Noise Ratio (SNR)** | 62 dBA | | **Acoustic Overload Point (AOP)** | 131 dB SPL | | **Supply Voltage (Vdd)** | 1.5V to 3.6V | | **Current Consumption** | 200 µA (typical) | | **Frequency Response** | 28 Hz to 20 kHz | | **Package** | 3.35 mm × 2.50 mm × 0.98 mm (LGA) | --- ### ## Key Features and Internal Architecture ### 1. High Acoustic Overload Point (AOP) The standout feature of the INMP411 is its ability to record audio up to **131 dB SPL**. This makes it ideal for applications where the environment is extremely loud (e.g., rock concerts, wind noise, or heavy machinery) where standard MEMS microphones would clip or distort the signal. ### 2. MEMS Sensor and Pre-amplifier The device consists of two main internal stages: * **MEMS Transducer:** A silicon diaphragm that converts sound pressure into a change in capacitance. * **Impedance Converter/Amplifier:** An internal ASIC that converts the capacitive change into a low-impedance analog voltage signal. ### 3. Power Supply Rejection (PSR) The chip features internal filtering that provides high PSR, meaning it is less susceptible to noise coming from the power supply rails (e.g., switching noise from a DC-DC converter). --- ### ## Typical Application Circuit When integrating the INMP411, a few external components are required for stability and signal integrity: ```markdown Vdd (1.8V - 3.3V) ----+-----------+ | | [C1] 0.1uF (VDD Pin) | | GND ------------------+-----------(GND Pin) | (OUTPUT Pin) --[C2] 10uF--> To Codec/MCU ADC ``` * **C1 (Decoupling Capacitor):** Placed close to the VDD pin to filter power noise. * **C2 (DC Blocking Capacitor):** Necessary because the analog output has a DC bias. A 10µF capacitor is typically used to ensure low-frequency sounds are not filtered out. --- ### ## Use Cases * **Smartphones:** For video recording in loud environments. * **Wearables:** Due to the ultra-low current consumption (200 µA). * **Industrial Monitoring:** Detecting mechanical failures or high-decibel alarms. * **Noise Cancellation:** As a reference microphone in ANC (Active Noise Cancellation) systems.