Design of CMOS Bandwidth Tunable Low-Pass Filter

Abstract

In this paper, a fully integrated bandwidth tunable low-pass filter based on 0.13\ \mu \mathrm{m}$ CMOS technology is proposed. Active-RC structure is selected as the basic filtering unit. In order to achieve better suppression characteristics, 3-stage Sallen-Key second-order low-pass filter units are adopted as cascading. The filter tunable by 15 steps from 4 to 60 MHz in steps of 4 MHz. The double cutoff frequency suppression is greater than 30dB and the IIP3 is 14.2dBm. The power supply voltage used for this chip is 1.2V with occupying 0.2 mm2 area.