The answer depends on how harsh of an environment and how much protection is required. For a microelectromechanical systems (MEMS) microphone, one of the most-harsh environments is the human body, since sweat and dirt can cause failures in traditional MEMS microphone architectures. Regarding the protection, the International Electrochemical Commission’s (IEC’s) IEC 60529 rating system defines different degrees of ingress protection (IP) for enclosures. In the two-digit coding system, the first digit indicates the dust protection level and the second digit is the water protection level. In both cases, the lowest level is zero and increasingly higher numbers indicate higher levels of protection with IP69K being the highest.
For harsh MEMS mic applications, Infineon Technologies’ IM73A135V01 analog XENSIV MEMS microphone is IP57 dust and water resistant. A proprietary MEMs architecture makes the silicon itself robust to IP57, without the need for additional costly package improvements such as the addition of a protective mesh. Sealed dual membrane MEMS technology at the microphone level prevents water or dust from entering between the membrane and backplate, that can cause mechanical blockage or electric leakage issues commonly observed in MEMS microphones. With sealed dual membrane technology providing built-in IP57 protection, IP57 rated microphones can be used to create IP68 devices, requiring only minimal mesh protection.
The IM73A135V01 microphone’s environmental robustness combined with Industry leading acoustic performance, makes it an excellent candidate for consumer devices that are on the body or handheld, such as True Wireless Stereo (TWS) earbuds, smart watches and smart phones.
The microphone’s environmental robustness is established by passing the following Standard Test Conditions:
IP5x dust resistance1 Arizona dust A4 coarse, vertical orientation, sound hole upwards for 10 cycles (15 minutes sedimentation and 6 sec blowing).
IPx7 water immersion2 After temporary immersion in 1 meter of water for 30 minutes, the microphone is tested 2 hours after removal.
[1] The number “5” stands for the dust ingress rating with the capacity to withstand the effects of fine, abrasive dust particles.[2] The number “7” identifies the level of liquid protection and the ability to withstand immersion up to 1 meter.
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