ST 公司的MP34DT01是超小型低功耗全方位数字MEMS麦克风,具有容性传感元件和IC接口,单电源工作,声学过载点120 dBSPL,信噪比63dB,全方位灵敏度,灵敏度-26dBFC,PDM输出,主要用在手机,笔记本电脑,手持媒体播放器(PMP),VoIP,语音识别,数码相机和摄像机,防盗系统等.本文介绍了MP34DT01主要特性,以及采用MP34DT01和STM32 MCU的STEVAL-MKI117V1演示板主要特性,电路图,材料清单和PCB布局图.
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应用:
■ 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
图1.STEVAL-MKI117V1演示板外形图:左,顶视图,右,底视图
图2.STEVAL-MKI117V1演示板电路图(1)
图3.STEVAL-MKI117V1演示板电路图(2)
STEVAL-MKI117V1演示板材料清单:
图4.STEVAL-MKI117V1演示板PCB布局图:顶层
图5.STEVAL-MKI117V1演示板PCB布局图:底层
