A digital background calibration method for a current-steering digital-to-analog converter (DAC) is presented. The algorithm uses one comparator for calibration and corrects for current-source mismatch, which causes DAC nonlinearity. The DAC is split into two identical channels, with each channel consisting of a main DAC and an auxiliary DAC. The comparator examines the difference between the two channels to generate a binary error signal, which is used in a sign-LMS algorithm. Simulation results are presented to demonstrate the split-calibration algorithm.