A 0.9V 3rd-order single-OPAMP analog filter in 28nm CMOS-bulk

Abstract

A 3rd-order 132MHz cut-off frequency low-pass filter in 28nm CMOS-bulk technology is presented. Challenges related to the design of analog circuits in 28nm CMOS-bulk process node have been faced and mitigated operating at both architecture and circuit design level. The filter is based on an improved Active-gm-RC structure, where both poles of a Miller-compensated Opamp have been used for synthesizing the 3rd order filter transfer function. The proposed circuit solution enables high linearity (IIP3=11.5dBm at 21&22MHz input tones) even if the supply voltage is limited to 0.9V. Moreover, the power consumption is kept as low as 340μ\ν without that the Signal-to-Noise ratio (60dB) is penalized. The achieved Figure-of-Merit is 164dB resulting the highest with respect to the state-of-the-art.