Dynamic element matching with signal-independent element transition rates for multibit ΔΣ modulators

This paper presents a novel dynamic element matching (DEM) technique for multi-bit ΔΣ digital-to-analog converters (DACs). The proposed technique can address errors due to both static element mismatch and dynamic inter-symbol-interference (ISI). The proposed technique ensures no ISI-induced distortion even at large signal amplitudes by de-correlating the instantaneous number of DAC transitions from the signal. It can shape the total number of transitions and whiten the individual transition sequence, thereby significantly reducing the in-band ISI errors. The proposed technique can be easily extended to higher-order shaping for both static mismatch and ISI errors. An efficient hardware implementation based on the vector-quantizer mismatch shaping framework is also presented. Simulation results show that the proposed technique can significantly improve DAC linearity in presence of both static mismatch and dynamic ISI errors.