STMicroelectronics STEVAL-MKI139V3

Overview

STEVAL-MKI139V3 from STMicroelectronics is a microphone coupon evaluation board hosting four MP23AB02B analog MEMS microphones, each with -38 dBV sensitivity, 64 dB SNR, 120 dBSPL acoustic overload point, 100 Hz–10 kHz frequency response, and 1.6–3.6 V supply range. It enables rapid performance validation in beamforming and multi-microphone audio capture systems.

For engineers reviewing the STEVAL-MKI139V3 datasheet, STEVAL-MKI139V3 pinout, STEVAL-MKI139V3 application, or STEVAL-MKI139V3 equivalent, this board supports quick detachment of individual microphone PCBs for isolated characterization, provides standardized analog output interfaces (OUT/VDD/GND), and delivers verified acoustic performance metrics under real-world bias conditions.

Technical Context

The board implements four identical analog MEMS microphone channels, each based on the MP23AB02B transducer die with integrated ASIC signal conditioning. Each channel features a single-pole RC high-pass filter (C1 = 1 nF, R internal) and output coupling capacitor (C2 = 1 µF) to block DC offset and ensure compatibility with downstream ADC inputs.

All four microphones share common power and ground routing optimized for low-noise analog operation. The coupon layout allows mechanical decoupling via PCB separation, minimizing inter-channel crosstalk and enabling independent mounting orientation for directional testing.

Key Specifications

Availability

STEVAL-MKI139V3 is available at Aetrix Electronics and suitable for multi-microphone array development, voice interface prototyping, and acoustic beamforming validation requiring stable component supply and documented analog performance.

Supply support for STEVAL-MKI139V3 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, sensors, power ICs, and analog components for industrial, automotive, and consumer applications.

This board belongs to ST's STEVAL sensor evaluation platform family, engineered to accelerate sensor integration by providing validated signal chain implementations, detachable coupon layouts, and application-ready electrical interfaces.

FAQ

What is the purpose of the coupon design on STEVAL-MKI139V3?

The coupon design allows physical separation of individual microphone PCB sections using pre-scored breakaway edges. This enables mechanical isolation for directional testing, independent mounting on enclosures or arrays, and elimination of board-level crosstalk during acoustic characterization-without requiring custom PCB fabrication.

Can STEVAL-MKI139V3 be powered directly from a 3.3 V microcontroller I/O rail?

Yes. The MP23AB02B microphones operate within 1.6–3.6 V, making 3.3 V a fully compliant supply voltage. The board includes no onboard regulation, so the input must be clean and well-decoupled; ST recommends adding local 100 nF ceramic capacitance near each VDD pin when interfacing with MCU rails.

What is the function of C1 (1 nF) and C2 (1 µF) shown in the schematic?

C1 forms a high-pass filter with the microphone's internal impedance to suppress sub-100 Hz mechanical resonance and power-supply ripple. C2 blocks DC offset from the analog output, ensuring only the AC audio signal reaches the ADC input-critical for preserving dynamic range and preventing input stage saturation.

Is STEVAL-MKI139V3 RoHS compliant?

Yes. As stated in the official data brief, the board is RoHS compliant. All solder mask, substrate materials, and surface finishes meet EU Directive 2011/65/EU requirements, including restriction of lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE substances.