Gain and Bandwidth Programmable Fourth-Order Multiple Feedback Butterworth Low-Pass Filter for C–V2X Applications

• Published in: Journal of circuits, systems, and computers Vol. 31; no. 9
• Main Authors: Barin, Furkan, Zencir, Ertan
• Format: Journal Article
• Language: English
• Published: Singapore World Scientific Publishing Company 01.06.2022; World Scientific Publishing Co. Pte., Ltd
• Subjects: Bandwidths; CMOS; Feedback; Filter design (mathematics); Low pass filters; Low voltage; Topology; Transfer functions; cellular vehicle-to-everything; Multiple-feedback; tunable; Butterworth low-pass filter
• ISSN: 0218-1266; 1793-6454
• DOI: 10.1142/S021812662250164X

A gain and bandwidth tunable active-RC multiple-feedback (MFB) fourth-order low-pass filter is presented, which exhibits four different bandwidths of 10, 20, 30 and 40 MHz and four different gain settings of 0, 4, 8 and 12 dB to meet the requirements of the cellular vehicle-to-everything (C-V2X) standards. The filter uses the cascade of two biquad MFB cells. Gain and bandwidth programmability is achieved by using programmable capacitor and resistor arrays. A logic block is implemented in the filter to adjust the gain transfer function for every tuning option. Also, two-stage miller op-amp topology is chosen to implement biquad MFB cells for minimum complexity and maximum efficiency in low voltage operation. The filter is designed in 65-nm CMOS technology and occupies a 0.181 mm2 area and it totally consumes 13.41 mW from the 1.2 V supply voltage. To the best of the author’s knowledge, this work is the first CMOS baseband filter design that includes both gain and bandwidth programmability implemented for C-V2X applications.