GAIN IMPROVEMENT OF TWO STAGE OPAMP THROUGH BODY BIAS IN 45NM CMOS TECHNOLOGY

Sanjay Kumar, Pathak Jay, Rajendra Prasad

Abstract: Gain is an important parameter of an operational amplifier which decide accuracy and speed of it. Number of design techniques (gain boosting, cascoding, cascading etc.) available, which may improve gain of an OPAMP. This paper includes body bias technique to improve gain, thereby speeds up operation of an OPAMP. Technology scaling doesnt have much impact on threshold voltage of transistor which leads to reduced DC gain of an OPAMP, thereby slowdown their operation. Body bias technique cross the barrier of threshold voltage limitation of technology scaling, hence OPAMP exhibits improved DC gain. The proposed OP AMP having DC gain of 57.83 dB which is 5dB more than classical OP AMP design using transistor pair Unity gain bandwidth is 74 MHz. The op amp is designed in 45nm CMOS technology; simulation and result were carried out in Cadence with 1.3V power supply.

Keywords: Body bias, Pseudo Cascode compensation, and Transistor pair.

DOI: https://doi.org/10.15623/ijret.2014.0304168