A CML XOR logic circuit is provided that includes a pair of pull-up transistors, a pair of current source transistors and a logic switch network coupled between the pull-up transistors and the current source transistors. The logic switch network including a plurality of transistors divided into a first branch, a second branch and a third branch. A tail current flows through the first branch, the second branch or the third branch based on at least two input signals to the plurality of transistors.