Improved data scramblers and swapper cells and improved digital to analog converters are provided. The improved swapper cells permit data to be propagated through the cell immediately upon receipt. The determination of whether to swap data or pass it directly through is based on a history of data values propagated through the cell, but is independent of the values of the particular inputs being swapped. The data scrambler is structured to permit the possible data inputs on swapper cells in the scrambler to be restricted. A minimum delay data scrambler for use in a fast digital to analog converter is disclosed using these components.