High-Gain Super Class-AB Bulk-driven Sub-threshold Low-Power CMOS Transconductance Amplifier for Biomedical Applications

Rakesh Kumar Pandey, Vijaya Bhadauria, Vinod Kumar Singh


This article describes a high-gain sub-threshold region-operated bulk-driven (BD) super class-AB power-efficient single-stage operational transconductance amplifier (OTA) with enhanced unity gain frequency (UGF). The proposed amplifier has a BD adaptively biased flipped voltage follower (FVF)  differential input pair functioning in class-AB mode to raise the dynamic current and subsequently raise the UGF, and slew rate. Additionally, the core circuit of the proposed OTA employs partial positive feedback (PPF) to magnify the circuit's effective input transconductance and gain. Moreover, the circuit's overall gain is moved up by using three additional low-power current mirror loads, two of which are FVF current mirrors and one of which is a self-cascode current mirror, placed at the output. The proposed OTA circuit and its traditional counterpart are developed and simulated on the Cadence Spectre tool by exploiting UMC 0.18μm CMOS process technology, both circuits are biased with a minimal supply of 0.5V. The simulation results exhibit that the proposed circuit delivers 72.35dB open loop DC gain, 61.33º phase margin, and 18.706 kHz UGF with a consumption of only 62.82nW power. The performance outcomes ensured the suitability of the proposed OTA circuit for biomedical applications.


Adaptive biasing;Bulk-driven OTA;FVF;Partial Positive Feedback;Self-cascode

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DOI: https://doi.org/10.33180/10.33180/InfMIDEM2023.202


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