ABSTRACT
Operational amplifiers (opamps) are designed with numerous constraints, such as direct current gain, bandwidth, supply voltage, power consumption, slew rate, noise, offset, output signal swing, input common-mode range, and output load driving capability. In integrated circuits, opamps are made fully differential to make them immune to noises from the supply or bias lines. However, most integrated complementary metal-oxide semiconductor opamps have no output buffers because most of them drive only internal capacitive loads. The transient response of opamps in feedback is discussed based on the assumption that the amplifier is operating in small-signal linear mode. The transient step response is mainly dominated by pole frequencies and phase margin. That is, the linear model of transistor is still valid, and the steady-state analysis like frequency response can provide valuable information on the transient step response. Most transient responses can be understood using either a sinusoidal or step function.
