MEMS Microphone
Overview
The LinkMems LMA3729T381-OY3S is a high-performance MEMS digital microphone featuring omnidirectional polar pattern, high SNR (63dB(A)), and ultra-compact package (3.76 × 2.95 × 1.00mm). Its low power design and excellent acoustic performance make it an ideal choice for voice interaction, smart speakers, and IoT voice devices.
1. Product Overview
1.1 Key Features
- Omnidirectional polar pattern: 360° uniform sound pickup, suitable for all-scenario voice acquisition
- High signal-to-noise ratio: 63dB(A) SNR, ensuring clear voice capture quality
- Low power consumption: Operating current of only 75µA, suitable for battery-powered devices
- Digital output: PDM digital interface with strong anti-interference capability and long transmission distance
- Ultra-compact package: 3.76 × 2.95 × 1.00mm, weight <0.03g, saving space
- Environmental compliance: RoHS compliant, halogen-free, meeting green manufacturing requirements
1.2 NE301 Application Scenarios
In the NE301 sensor expansion board, the MEMS microphone serves as a sound event trigger sensor, capable of detecting specific sound events such as glass breakage and abnormal noises to trigger NE301 snapshot capture. In security scenarios, sound triggering complements PIR/radar triggering to form a multi-detection mechanism, reducing missed reports.
| Application Scenario | Description |
|---|---|
| Security Alert | Detects abnormal sounds such as glass breakage, immediately triggering NE301 snapshot capture |
| Environmental Monitoring | Detects abnormal equipment operating noise, triggering event snapshots |
| Voice Interaction | Detects voice commands or keywords, linking NE301 snapshot capture |
| IoT Gateway | Sound events trigger snapshots, working with other sensors for multi-modal perception |
2. Specifications
2.1 Basic Parameters
| Parameter | Specification |
|---|---|
| Model | LMA3729T381-OY3S |
| Manufacturer | LinkMems Acoustic Technology |
| Type | MEMS digital microphone |
| Package | 3.76 × 2.95 × 1.00mm (4-pin) |
| Weight | <0.03g |
| Supply Voltage | 1.6V ~ 3.6V (typical 2.0V) |
| Output Interface | PDM digital output |
| Acoustic Port Diameter | Ø0.325mm |
2.2 Performance Parameters
| Parameter | Condition | Min | Typical | Max | Unit |
|---|---|---|---|---|---|
| Polar Pattern | — | — | Omnidirectional | — | — |
| Sensitivity | 94dB SPL @1kHz | -39 | -38 | -37 | dB |
| Output Impedance | 94dB SPL @1kHz | — | 400 | — | Ω |
| Operating Current | 94dB SPL @1kHz | — | 75 | — | µA |
| Signal-to-Noise Ratio | A-Weighted | — | 63 | — | dB(A) |
| Total Harmonic Distortion | 94dB SPL @1kHz | — | 0.15 | — | % |
| Acoustic Overload Point | 10% THD @1kHz | — | 125 | — | dBSPL |
| Power Supply Rejection Ratio PSRR | 200mVpp @1kHz | — | 60 | — | dB |
2.3 Operating Conditions
Absolute Maximum Ratings
| Parameter | Range |
|---|---|
| VDD to GND | -0.3V ~ +3.9V |
| OUT to GND | -0.3V ~ +3.9V |
| Input Current (any pin) | ±5mA |
| Temperature Range | -40°C ~ +100°C |
Reliability Test Standards
Sensitivity variation after each reliability test should be controlled within ±3dB.
3. Pin Definition
The LMA3729T381-OY3S uses a 4-pin package with the following pin definitions:
| Pin # | Name | Type | Description |
|---|---|---|---|
| 1 | VDD | Power | Power supply input (1.6V ~ 3.6V) |
| 2 | GND | Ground | Ground |
| 3 | GND | Ground | Ground |
| 4 | OUT | Signal | PDM digital output signal |
Note: Pin 2 and Pin 3 are both GND pins. During PCB layout, it is recommended that both GND pins be reliably grounded to reduce ground impedance and improve signal integrity.
| Item | Information |
|---|---|
| Document Version | v1.0 |
| Last Updated | 2026-04-08 |