Realizations of CMOS fully differential current followers/amplifiers

Three CMOS realizations of fully differential current followers (amplifiers) are presented. Their various characteristics are determined and evaluated. In general, the proposed circuits exhibit low input resistances, high output resistances, and low common-mode gains. However, interesting differences showing the advantages and disadvantages of each topology are highlighted. Simulation results obtained using 0.18 mum CMOS models are provided.