| Operational amplifier is an integral part of analog circuits. With the advent of portable device technology, power consumption has become an area of concern.;To reduce power consumption and improve battery life performance, supply voltages are scaled. This leads to a reduced input common mode range for an operational amplifier. A rail-to-rail amplifier composed of complementary CMOS differential pairs is employed to obtain a wider input common mode range.;However, the complementary differential pairs, when operated in parallel lead to a large variation in the total transconductance thereby making the circuit highly unstable. A simple and novel technique to remedy this is to use a diode connected NMOS to shift the transition region of the NMOS differential pair. This circuit is simple and consumes less power.;XFAB 0.35microm process technology is used in the design of the circuit. Cadence SPECTRE simulator is used for all the simulations. |
