A Reconfigurable-Band Analog Filter Standard-Cell Based on Differential/Single Input Signaling

• Published in: IEEE access 2024, Vol.12, p.13586-13600
• Main Authors: Diaz-Sanchez, Alejandro, Zamora-Mejia, Gregorio, Rocha-Perez, Jose M., Vazquez-Gonzalez, Jose L., Zapata-Rodriguez, Uriel G.
• Format: Article
• Language: English
• Subjects: analog standard cell; Analogue filters; Circuits; CMOS; continuous-time filter; Operational amplifiers; Power consumption; Reconfiguration; Transconductance; universal filter; very-low frequency
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2024.3358212

This work presents a reconfigurable-band analog filter capable of performing the low-pass, high-pass, band-pass or all-pass functions. The proposed filter is a simple and compact cell composed of only two RC networks and one differential Operational Transconductance Amplifier (OTA). To select the desired filter type, two configurations must be done: 1) the two RC network shall be configured as low-pass/low-pass, high-pass/high-pass or low-pass/high-pass, 2) the input signals must be fed in differential or single mode. To validate theory and simulations, the proposed reconfigurable-band filter was designed, fabricated and measured to meet the biomedical band (0.1 Hz - 10 kHz) in a [Formula Omitted] CMOS standard fabrication process. To achieve the extremely low RC time constants imposed by the biomedical band, the R element was implemented using PMOS high-value programmable resistor. The prototype exhibits a silicon area of [Formula Omitted] x [Formula Omitted] and a power consumption of [Formula Omitted] using a ± 0.8 V symmetric power supply. Due to this circuit’s ability to perform four filter-functions, its operation band can be tuned over five decades, its power consumption is in the nano and micro-watt regime, and it is area compact, the proposed analog filter is a suitable candidate for being an analog standard-cell.