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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: 
DM00039779[1].pdf
(282.79 KB)
DM00051593[1].pdf
(357.92 KB)
來源：網絡 |
