The circuit symbol of fully differential COA is reported in
Figure 1. COA ideally exhibits zero input resistance and
infinite output resistance and current gain.
Differential signalling has many advantages such as;
better noise performance, reduced even-odd harmonics
and increased dynamic range. However limited number of
the COA designs is fully differential in the literature [4 -
6]. Unfortunately, these COA’s do not offer both high
drive capability and wideband operation, crucial point of
current-mode circuits.