Modified mismatch-shaping for continuous-time delta-sigma modulators

By noise-shaping the error caused by element mismatch in a multi-bit DAC, mismatch-shaping allows multi-bit quantizers to be used in /spl Delta//spl Sigma/ ADCs and DACs without sacrificing the inherent linearity of single-bit architectures. Unfortunately, mismatch-shaping turns the DAC elements on and off frequently and thus accentuates dynamic effects. By taking into account the effects of element switching, "modified mismatch shaping" yields a continuous-time /spl Delta//spl Sigma/ DAC whose performance is insensitive to both element mismatch and element switching dynamics. Experimental results confirm the effectiveness of the technique.