Optimum selection of capacitive array for multibit Sigma-Delta modulators without DEM

A method for a smart selection and sequencing of unity capacitors in a multibit DAC is proposed. The approach, suitable for the DAC nonlinearity correction in sigma-delta modulators, obtains results that are better than the dynamic element matching. Key of the technique is an off-line self-measurement of mismatches. The results significantly improve when the DAC capacitors are selected from a set that is larger than required. An affordable silicon area overhead avoids extra power consumption during the normal operation of the converter.