English 
Chinese In the realm of portable smart devices, the demand for high-quality audio capture has never been greater. Micro-Electro-Mechanical Systems (MEMS) microphones have become the cornerstone of this evolution, offering compact size and low power consumption. However, integrating multiple MEMS microphones into devices necessitates scaling down the microphone package, which includes both the sensor and the readout electronics. Achieving this miniaturization without compromising performance is a significant challenge.
Innovative Circuit Solutions in 55nm CMOS Technology
Recent advancements have explored the use of 55nm CMOS technology to design low-noise MEMS microphone interfaces. This technology node offers a balance between reduced area and production costs. Two notable circuit topologies have emerged:
- Super Source Follower (SSF): An evolution of the fundamental source follower topology, the SSF utilizes either PMOS or NMOS input devices. This design implements a constant charge readout method for capacitive microphones, effectively reducing flicker noise, which is particularly detrimental in low-frequency applications like audio systems.谷歌专利
- Differential Difference Amplifier (DDA): This topology introduces complexity and elegance to the microphone system. It achieves low current consumption and offers versatile gain programmability. However, further optimization is required to enhance linearity and noise performance beyond current products.
Both SSF and DDA topologies demonstrate considerable advantages in area and power consumption, making them competitive alternatives to existing solutions, even when utilizing deep sub-micron technology nodes like 55nm.
Performance Benchmarks
The primary challenges in designing audio circuits include achieving high linearity, with Total Harmonic Distortion (THD) reaching 10% (Acoustic Overload Point, AOP) for amplitude values over 130 dB SPL, and maintaining output integrated noise levels within the audio frequency range (20 Hz to 20 kHz) below -108 dBV(A). Silicon test-chip measurements indicate that these specifications are largely met by the proposed circuits, validating the efficacy of the SSF and DDA designs in 55nm CMOS technology.
Our Company’s Commitment to Innovation
At Wuxi Silicon Source Technology Co., Ltd.(SISTC), we are dedicated to pushing the boundaries of MEMS microphone technology. Our expertise in integrating advanced circuit designs within compact packages ensures that our products meet the ever-evolving demands of the consumer electronics market. By adopting cutting-edge technologies like 55nm CMOS, we strive to deliver microphones that offer superior audio quality, low power consumption, and minimal footprint.
Further Reading
For more in-depth information on this topic, consider exploring the following resources:
