ST 公司的MP34DT01是超小型低功耗全方位數字MEMS麥克風,具有容性傳感元件和IC接口,單電源工作,聲學過載點120 dBSPL,信噪比63dB,全方位靈敏度,靈敏度－26dBFC,PDM輸出,主要用在手機,筆記本電腦,手持媒體播放器(PMP),VoIP,語音識別,數碼相機和攝像機,防盜系統等.本文介紹了MP34DT01主要特性,以及采用MP34DT01和STM32 MCU的STEVAL-MKI117V1演示板主要特性,電路圖,材料清單和PCB布局圖.
The MP34DT01 is an ultra-compact, low-power,omnidirectional, digital MEMS microphone built with a capacitive sensing element and an IC interface.
The sensing element, capable of detecting acoustic waves, is manufactured using a specialized silicon micromachining process dedicated to produce audio sensors.
The IC interface is manufactured using a CMOS process that allows designing a dedicated circuit able to provide a digital signal externally in PDM format.
The MP34DT01 has an acoustic overload point of 120 dBSPL with a 63 dB signal-to-noise ratio and –26 dBFS sensitivity.
The MP34DT01 is available in a top-port, SMDcompliant, EMI-shielded package and is guaranteed to operate over an extended temperature range from -30℃ to +70℃.
MP34DT01主要特性:
■ Single supply voltage
■ Low power consumption
■ 120 dBSPL acoustic overload point
■ 63 dB signal-to-noise ratio
■ Omnidirectional sensitivity
■ –26 dBFS sensitivity
■ PDM output
■ HCLGA package
– Top-port design
SMD-compliant
– EMI-shielded
– ECOPACK® , RoHS, and “Green” compliant
MP34DT01應用:
■ Mobile terminals
■ Laptop and notebook computers
■ Portable media players
■ VoIP
■ Speech recognition
■ A/V eLearning devices
■ Gaming and virtual reality input devices
■ Digital still and video cameras
■ Antitheft systems
MEMS microphone demonstration board based on the MP34DT01 and STM32
The purpose of the STEVAL-MKI117V1 demonstration board is to provide an example of the decoding and streaming of digital MEMS microphone outputs.
The STEVAL-MKI117V1 demonstration board hosts the MP34DT01 (bottom-port digital microphone), working as a sensor, and the STM32F107RC microcontroller, working as an audio decoder.
These microphones are analog-to-digital transducers. They are able to sense sound pressure and convert this signal into a digital signal using the PDM technique.
The STM32 microcontroller decodes the PDM signal coming from the microphones and streams the audio via the USB.
The STEVAL-MKI117V1 demonstration board is a sound card automatically recognized by the PC as an audio device. Connection is made through a USB cable which also supplies the board and then streams the collected audio.
STEVAL-MKI117V1演示板主要特性:
■ Powered and connected to PC through USB
■ Sound card automatically recognized by the PC as an audio device
■ The onboard microphones are digital MEMS devices
■ MEMS microphones provide a high frequency data stream (1 to 3.25 MHz) of 1-bit digital samples (PDM technique)
■ Audio collected from the microphones is sent to the PC through the USB
■ LED status indicator
■ RoHS compliant
圖1.STEVAL-MKI117V1演示板外形圖:左,頂視圖,右,底視圖
圖2.STEVAL-MKI117V1演示板電路圖(1)
圖3.STEVAL-MKI117V1演示板電路圖(2)
STEVAL-MKI117V1演示板材料清單:
圖4.STEVAL-MKI117V1演示板PCB布局圖:頂層
圖5.STEVAL-MKI117V1演示板PCB布局圖:底層
詳情請見:
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/DM00039779.pdf
和
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/DM00051593.pdf