A Nanowatt Area-Efficient 16-Channel Bandpass Filterbank with Floating Active Capacitance Multiplier for Acoustic Signal Processing

This paper introduces an area-efficient nanowatt 16-channel bandpass filterbank tailored for acoustic signal processing in Artificial Internet of Things (AIoT) sensor systems. Integration of a floating active capacitance multiplier (FACM) adeptly addresses the inherent challenge of increased area in source-follower-based filters due to their larger capacitance. Compared to conventional gm-C filters, this work offers reduced power consumption, a more straightforward structure, and tunability. In a standard 0.13-μm CMOS process, simulations reveal that the filterbank's frequency range spans from 92 Hz to 5060 Hz with a gain of 17 dB, and a total power consumption of 97 nW for the 16 channels. When benchmarked against recent bandpass filters, this work achieves an impressive area efficiency of 0.038 mm²/channel and superior linearity. Such a compact and energy-efficient design offers a competitive solution for analog feature extraction in edge AI applications.