A randomized thermometer-coding digital-to-analog converter (DAC) for the
reduction of harmonic distortion due to non-ideal circuit mismatch is
presented. The present invention introduces a new dynamic element
matching technique that contains three properties of randomization,
consecutive selection and less element switching activity to achieve good
spurious-free dynamic range and small maximum output error. The topology
uses a bank of 1-bit DAC elements, whose outputs are summed to produce a
multi-level analog output. The binary digital input is encoded to be
thermometer code. During a randomization period, the thermometer code is
barrel-shifted to a specific starting position where the position is
generated randomly. Thus, the DAC noise is randomized with less element
switching activity and consecutive selection.