Random Swapping Dynamic Element Matching Technique for Glitch Energy Minimization in Current-Steering DAC

Dynamic element matching (DEM) has been employed to increase the spurious-free dynamic range of data converters. However, generic DEM techniques will induce additional glitch energy. This brief describes a type of the DEM method called random swapping thermometer coding for the implementation of Nyquist-rate current-steering digital-to-analog converters. The selecting direction for a sequence of unit current sources will be randomly changed. Furthermore, combining the restricted jumping technique simultaneously can further smooth low-frequency idle tones. This approach can minimize the number of switched elements as codes change, while achieving good spectrum purity as other DEM implementations. Examples from a behavior-level simulation for 6-bit converters are given to illustrate harmonic suppression and glitch energy improvement achieved by the proposed algorithm.