Operational amplifier design with gain-enhancement differential amplifier

This paper discusses a gain-enhancement differential amplifier circuit with positive feedback. The circuit is designed with short-channel MOSFETs, low power, and low voltage, resulting in DC gain improvement over a conventional complementary-metal-oxide-semiconductor (CMOS) diff-amp and comparable to a known published diff-amp circuit. In addition, noise and distortion analyses are shown on diff-amps. This paper also describes two operational amplifier (op-amp) circuits, which are designed with the new gain-enhancement diff-amp.