Designing, Simulation, and Performance-based Screening for a Power-Efficient Operational Transconductance Amplifier (OTA) Utilizing CNTFET Technology at a 22nm Node for Biomedical Applications

Extremely low-frequency variations are often associated with physiological signals. Therefore, while acquiring physiological signals of human origin, the signal acquisition system interferes with several artefacts and noises. Thus, acquiring noise-free physiological signals of human origin using miniaturized, low-power external or implantable measurement devices is paramount for diagnostic and therapeutic purposes. The OTA serves as a basic component in analog signal-processing circuits, making it ideal for low-frequency electronic signal processing. Pure CNTFET, CNTFET-MOSFET hybridized, and MOSFET-based OTA-C circuits suitable for processing biomedical signals were designed at a 22 nm technology node and simulated to assess their performance using HSPICE. The design parameters included a Carbon Nanotube (CNT) diameter of 1.5 nm (with a chirality of (19, 0), a total of 10 CNTs/CNTFETs, and a pitch of 20 nm. The circuit was designed using a channel length of 22 nm and a channel width of MOSFET 381.5 nm. Following a curious analysis of the performance parameters, pure CNTFET-based OTA-C was screened as the most appropriate model for biomedical applications among all the four proposed OTA-C models as it exhibited high gain (38 dB), high phase margin (90.7◦), high unit gain frequency (19 MHz), and low power consumption (29 μW). The proposed pure CNTFET-based OTA-C was a high-gain-low-power-consuming stable building block (amplifier) appropriate for generating various diagnostic and therapeutic biomedical devices.