A 130dB SPL 72dB SNR MEMS Microphone Using a Sealed-Dual Membrane Transducer and a Power-Scaling Read-Out ASIC

This work describes a microphone system featuring a new MEMS transducer based on a sealed-dual membrane (SDM) design paired with the latest generation of digital read-out ASIC. State-of-the-art noise performance is achieved thanks to significant optimizations both on the MEMS as well as on the ASIC side. The SDM design reduces significantly the magnitude of one of the main noise contributors by moving the air gaps to a sealed low-pressure chamber. The ASIC features an unconventional read-out amplifier based on a power-scalable current-feedback architecture as well as a reconfigurable
$\Delta \Sigma $
modulator allowing to trade-off signal-to-noise ratio (SNR) versus power consumption. The microphone system achieves an SNR of 72dB(A) supporting an acoustical overload point (AOP) of 130dB SPL. This represents a significant improvement to current state-of-the-art digital microphones.