Adaptive biased operational amplifier with improved Slew-Rate

The work proposes a novel design of an Operational Amplifier which uses an Adaptive biased Differential Amplifier stage for biasing. When Operational Amplifier is configured as a Buffer, the output signal gets distorted even at low frequencies and it does not follow the input signal. To resolve this issue the designers need to go for alternative biasing schemes. On the other hand, when the Operational Amplifier is configured using this new Adaptive biasing technique and pulse input impressed over it, the new circuit delivers a distortion-less output even at higher frequencies. This improves the Slew-Rate of the Operational Amplifier. With and without adaptive biasing technique, the Slew-Rate of the operational amplifier is calculated and compared it with original circuitry. The input/output characteristic of the proposed design is discussed. Designed circuit is simulated in a proprietary 180 nm CMOS process, using Cadence Spectre and UMC models.