Current-mode phase rotator with partial phase switching

In one illustrative embodiment, an apparatus for a current-mode phase rotator with partial input phase switching comprises a mixer, wherein the mixer is a four quadrant current-mode mixer comprised of four interpolation buffers, wherein each interpolation buffer receives as input a clock phase from a set of four equidistant clock phases, and a set of two-output current-steering digital to analog converters that supply tail currents to the mixer wherein a first digital to analog converter has additional switches to connect each of two outputs to one of two polarities of a given clock while each remaining digital to analog converter has no additional switches and has two outputs supplying current only to two different polarities of a same clock phase wherein steering the current during incremental rotation about a phase circle defines an octagonal shaped phase envelope.