A 1-V high-gain two-stage self-cascode operational transconductance amplifier

Abstract

This paper presents design of two-stage operational transconductance amplifier (OTA) using self-cascode MOSFET to achieve high gain with a low-supply voltage. To improve the gain of OTA a positive feedback is created by cross coupling the bulk terminals of the input stage load transistors. The proposed design is implemented in a standard 65 nm CMOS process with a supply voltage of 1 V. The designed self-cascode OTA affords a DC gain of 78 dB, unity gain frequency of 191 MHz and a phase margin of 63.5° with a small process, voltage, temperature (PVT) variations.