Low Noise Amplifiers for MEMS Microphones

Nowadays wireless technology, different kind of sensor nodes, and IoT devices have incorporated hearing devices, which has become a dominant component. One of the reasons is due to their non-compact size and power consumption. MEMS are the most common and massively produced microphones for different applications such as hearing aid devices which are used by patients with hearing impairment to help with hearing problems, IoT devices, mobile phones, laptops, and so on. The key feature of MEMS microphones is the adaptability to different kinds of electronic interfaces and electric properties that make them attractive to use instead of other types of microphones technologies. MEMS microphones can be used in an analog or digital structure. The amplifier is the main component in MEMS microphones. This article presents a detailed study of different topologies of amplifiers that have been made in both analog and digital MEMS microphones which are used for low-noise applications. Results and typical parameters obtained are presented.