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

In this paper, a CMOS implementation of a current operational amplifier (COA) with a differential input and a differential output is described. The amplifier is configured 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 mode operational amplifier (VOA). In this design, the simulation results exhibit an open-loop differential gain of 51.71 dB with the gain-bandwidth product 314 MHz and a settling time of 14 ns.