This paper presents an ultra low power process-insensitive two stage CMOS OP-AMP employing bulk-biasing technique realised in a standard 45 nm CMOS technology. Bulk-Biasing technique has been employed to augment the DC gain of two stage CMOS OP-AMP without having any impact on its power
dissipation and output swing. In this work, high gain-bandwidth product (GBW) with appropriate phase margin is achieved through pseudo-cascode compensation approach which overcomes the drawbacks of Miller compensation technique also. Furthermore, the effect of width scaling on performance
metrics of proposed OP-AMP has been analysed. The designed OP-AMP exhibits enhanced DC gain of 94.2 dB, gain-bandwidth product (GBW) of 460 MHz and adequate phase margin of 80°; with fast settling response. Also, the proposed OP-AMP has power dissipation of 27 μW and leakage
current of 6.4 pA only. The design and optimisation of proposed OP-AMP is carried out at a power supply of 0.7 V under room temperature in Cadence Virtuoso tool.
