Third order inverse multifunction filter employing MOS resistors and capacitors

Abstract

This paper presents a systematic approach for the realization of multifunction filter that includes third order inverse low pass filter (ILPF), band pass filter (IBPF), and high pass filter (IHPF) using two Operational Transresistance Amplifiers (OTRAs), MOS resistors, and few number of capacitors. An operational activity of inverse filter configuration (IFC) can be easily realized by proper selection of switches. In ideal case, third order of the filter characterizes a total roll‐off of 60 dB/decade but the proposed design offers a roll‐off in the range of 48.09 dB/decade to 57.74 dB/decade which may arises due to passive component tolerance and some design parameters. The proposed design brings an improvement in roll‐off around 20%–44% in comparison to existing literatures. The multifunction filter frequency response (ILPF, IBPF, and IHPF) is observed by using PSPICE simulation in which the core of the filter “OTRA” is integrated with 180 nm Taiwan Semiconductor Manufacturing Company (TSMC) CMOS technology parameter. In addition to simulation results, hardware implementation of the proposed filter configuration validates the theoretical aspect of filter design.