A novel dynamic calibration approach for current-steering DACS

With increasing applications in telecommunication systems, high speed and high accuracy digital-to-analog converters (DAC) are becoming more and more important. Of particular interest is the dynamic performance at high frequencies. The dynamic performance is often characterized by the spurious free dynamic range (SFDR) and this is limited by the spectral harmonics that are mainly attributable to system nonlinearities. In this paper, the dynamic nonlinearity in the time domain is analyzed and its affect on the output waveform is discussed. A novel approach is presented to calibrate the dynamic errors. The validity of this approach is demonstrated with a 10-bit current steering DAC. Simulation results show that the nonlinear harmonics can be dramatically reduced and SFDR can be correspondingly improved by using this calibration scheme.