A gain boosted operational amplifier designed using positive feedback technique is presented in this paper. In this design, a differential output differential amplifier merged with a single output differential amplifier is used so that positive feedback can be applied appropriately. The proposed Op-Amp is designed in 0.18 mu m CMOS process using gpdk45nm library in Cadence virtuoso analog design environment. The simulation of proposed circuit results in 116.2dB gain, 281MHz UGB, 72 degree phase margin and 620 mu W power consumption. The Monte Carlo analysis of the circuit indicates that the variation of power supply voltage produces minimal effect on the gain and phase of the circuit.