AC coupled amplifier with a resistance multiplier technique for ultra-low frequency operation

This paper proposes a novel, tunable AC coupled capacitive feedback amplifier, exhibiting an ultra-low high pass corner frequency. is accomplished by actively boosting the output resistive value of MOS transistor in weak inversion. The circuit based on more general architecture, recently proposed authors, and analyzed terms its capability to achieve frequency operation, DC performance, noise. technique demonstrated via measurement results from fabricated test chip prototype using standard 0.18 µm CMOS technology. amplifier provides 20 mHz 475 mHz, consuming 4.71 ?W total area 0.069 mm2.