STMicroelectronics STEVAL-MKI155V3

Overview

STEVAL-MKI155V3 from STMicroelectronics is a microphone coupon daughterboard designed for acoustic evaluation of four MP34DT01-M digital MEMS microphones, supporting PDM output, 1.64–3.6 V supply, 120 dBSPL acoustic overload point, and 61 dB SNR. It interfaces with the STEVAL-MKI126Vx Smart Voice kit for beamforming and voice capture prototyping in compact embedded audio systems.

For engineers reviewing the STEVAL-MKI155V3 datasheet, STEVAL-MKI155V3 pinout, STEVAL-MKI155V3 application, or STEVAL-MKI155V3 equivalent, key selection factors include PDM interface compatibility with host MCUs (e.g., STM32L4/L5), mechanical decoupling via detachable PCBs per microphone, supply voltage range alignment with low-power voice processors, and RoHS-compliant board-level integration for qualification testing.

Technical Context

The board implements four identical MP34DT01-M microphones arranged for spatial audio sampling, each with omnidirectional response and -26 dBFS sensitivity referenced to 1 Pa. Power is distributed via a single VDD rail shared across all devices, with local 100 nF and 10 µF decoupling at each microphone's supply pin.

Signal routing uses dedicated differential-capable traces for PDM clock (CLK) and data (DATA), plus left/right channel select (L/R) and ground (GND) - enabling time-aligned multi-mic acquisition when mated to the STEVAL-MKI126Vx baseboard's digital audio interface.

Key Specifications

Availability

STEVAL-MKI155V3 is available at Aetrix Electronics and suitable for voice interface development, acoustic beamforming validation, and MEMS microphone qualification requiring stable component supply and documented ST reference design traceability.

Supply support for STEVAL-MKI155V3 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, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer applications.

This board belongs to ST's STEVAL sensor evaluation platform family, developed to accelerate prototyping and characterization of ST MEMS microphones and inertial sensors in real-world embedded audio and motion systems.

FAQ

What is the primary interface protocol used by the microphones on STEVAL-MKI155V3?

The MP34DT01-M microphones on this board use Pulse Density Modulation (PDM) output. Each microphone outputs a synchronous single-bit stream aligned to an externally supplied clock signal (CLK), with left/right channel selection handled via the L/R pin. This eliminates need for ADC conversion and enables direct connection to PDM-capable MCU peripherals like those found in STM32L4+ and STM32H7 series.

Can STEVAL-MKI155V3 operate independently without the STEVAL-MKI126Vx baseboard?

No - STEVAL-MKI155V3 is a daughterboard requiring the STEVAL-MKI126Vx Smart Voice kit for power, clock generation, and digital signal processing. It lacks onboard voltage regulation, clock source, or host interface; its J1/J2 headers are designed exclusively for mating with the baseboard's matching connector to route VDD, GND, CLK, DATA, and L/R signals.

How are the four microphones physically arranged and electrically isolated on this board?

The four MP34DT01-M microphones are mounted on separate, mechanically scored sub-PCBs that can be detached after scoring. Each sub-board includes dedicated 100 nF + 10 µF decoupling capacitors and shares only VDD and GND with the main board. Signal lines (CLK, DATA, L/R) are routed in parallel with matched trace lengths to preserve inter-channel timing alignment within ±2 ns.

Is STEVAL-MKI155V3 RoHS compliant and suitable for commercial production evaluation?

Yes - the board is RoHS compliant per STMicroelectronics' documentation (DocID027075 Rev 1). It uses standard FR-4 substrate, lead-free HASL finish, and components qualified for industrial temperature range. While intended for lab evaluation, its layout, BOM, and test points align with ST's production-grade reference design practices for voice interface subsystems.