Design Of Ultra-Low Power Operational Amplifier Biased On Near-threshold Voltage Technology

Nearly one hundred years ago, the first operational amplifier using vacuum tube appeared in the world. From then on, the volume、power dissipation and so on of operational amplifier have been a significant improvement, its performance is becoming closer to the ideal one. Nevertheless, operational amplifier is an important part of many analog and mixed-signal systems, with that the complexity of the operational amplifier brings out variety of functions. With the continuous improvement of semiconductor process technology, channel length of the transistor is reduced by degrees; the power supply voltage is also scaled down. At the same time, more complex design issues of operational amplifier have been put forward.With the reduction of channel length, operational amplifier gain is decreasing. For example, the gain of two-stage operational amplifier based on deep submicron is only a few dozen decibels, so the traditional two-stage amplifier can’t have met the demand for higher gain. In addition, the power dissipation is a perpetual theme in the field of integrated circuit design, which power dissipation is cut down means reducing waste of energy and energy saving. This paper is devoted on research and design of high gain amplifier, as well as the reducing of power dissipation under deep submicron process.1. The power dissipation of operational amplifier. With regard to integrated circuit, the power dissipation consists mainly of quiescent and dynamic, those ways of reducing power dissipation have body-driven, power gating and negative voltage bias technology and so on. However, it is the most important method of reducing power dissipation to decrease the power supply voltage. This paper is by means of lowering the power supply voltage to near the threshold voltage, also called near-threshold voltage technology, to accomplish the design of ultra-low power operational amplifier.2. The design of three-stage operational amplifier under near-threshold voltage. In this part, it will mainly discuss the design of three-stage operational amplifier in deep sub-micron technology, including the circuit architectural design, circuit analysis、performance simulation, and the design of bias circuit, so on and so forth.