Design and analysis of low-voltage current mode operational amplifier with differential-input and differential-output

In this work, a new CMOS current operational amplifier (COA) with fully differential input and differential output is proposed and analysed. The amplifier is implemented from a differential current mirror input transimpedance stage followed by a differential output transconductance gain stage. A differential mode design technique is proposed and used in the feedback circuit. This configuration is the current mode counterpart of the traditional voltage operational amplifier (VOA). The simulation results of the new COA are based upon the 0.5μm CMOS process and ±1.5V supply voltage. The new COA exhibits an open-loop differential gain of 51.71dB with the gain-bandwidth product 314MHz and a settling time of 14ns. The design and optimization guidelines of the new COA have been developed and analysed so that they can be applied to the design of high-performance COA.