A high DC-gain folded-cascode CMOS operational amplifier

The architecture of folded-cascode op-amp is commonly used in many analog applications. The cascode arrangement has high open-loop voltage gain in the low frequency range that make it easy to be designed as a high-speed operational amplifier. In this paper, we present the design of a fully differential folded-cascode operational amplifier that improves the limitation on the swing of the output signal of a common cascode architecture. The DC open-loop gain of the circuit is 4.7 K.