Design and Analysis of Low-Power Bulk-Driven Operational Transconductance Amplifier: A Self-Cascode Partial Positive Feedback Approach

Abstract

Achieving high-gain and low-noise operation of bulk-driven (BD) operational transconductance amplifier (OTA) with low-power consumption is a challenging task owing to inherent low transconductance and high noise in BD MOSFET. In this paper, we report a self-cascode partial positive feedback (SCPPF) approach-based BD OTA and have fairly compared the results with regular single MOS partial positive feedback (PPF) approach-based BD OTA. In comparison to regular BD PPF OTA, the proposed BD SCPPF OTA yields an improved gain of 68.71 dB, gain-bandwidth of 39.4 kHz, power consumption of 630 nW, output impedance of 0.4 MΩ and common mode rejection ratio of 134.4 dB for same input referred noise of 1.11 μV/√ Hz at frequency of 10 Hz and supply voltage of ±0.5 V. The area consumed by BD SCPPF OTA is 0.0523 mm2. The proposed BD SCPPF OTA can be possibly used to improve the performance of biomedical analog front-end sensing and signal processing systems.