High Gain More Stable Self Biased Two Stage Differential Amplifier for Bio-signal Processing

An Op Amp's main goal is to get the maximum open loop gain feasible in order to apply feedback concepts and build a more reliable system. The majority of op amp circuit types are built based on multistage nodes to obtain high gain with stability. This work presents self-biased two stage amplifier. In this differential amplifier inverters are used as input structures and self-biasing techniques is being used. The self-bias is done through negative feedback. This differential amplifier has fully complementary design. Detailed circuit analyses such as differential-mode, common-mode, CMRR, transient and AC analysis is being carried out. Finally, the experimental results those are relevant for an integrated circuit is designed using gpdk90nm technology and 1.8V. Final Simulations and results calculations were carried out in virtuoso Cadence tool.