Design and Simulation of Improved Folded Cascode Op-Amp Using Bulk Amplification in 0.18 um CMOS process

In this paper designing and simulation of Folded Cascade (FC) operational amplifier is presented. As a lot of researches have been done about Operational Amplifier (Op-Amp), FC op-amp is one of the good circuit structures which has high frequency response, DC gain and range of output swing. In this paper an improve folded cascode (IFC) is presented to enhance the DC gain of FC. This method does not limit the range of the output voltage swing, UGBW and phase margin of FC. IFC uses positive feedback. HSPICE simulations using level 49 parameters (BSIM3v3) in a typical 0.18μm CMOS technology result in ten times gain boosting , 58% enhancement in unity gain bandwidth compared and THD 16dB better than the FC. While the power consumption is increased by 25%.

Keywords:

Folded Cascode , Feed-forward , Bulk driven , Positive feedback