A Switching Sequence for Unary Digital-to-Analog Converters Based on a Knight’s Tour

This paper proposes a new switching sequence with the asymmetric placement of weighting elements for a unary digital-to-analog converter (DAC). The proposed sequence is based on a so-called knight's tour according to the modified Warnsdorf's rule. To estimate the efficiency of the proposed switching sequence, a 10-bit resistive DAC has been designed and fabricated in the UMC 180-nm technology. Experimental results show that in comparison with an array of weighting elements without compensation of the systematic error, the proposed switching sequence reduces the maximal integral (INL) and the mean INL by 20% on the average in the temperature range from -40 °C to 85 °C. Besides that, the maximal INL does not depend on the temperature, while the mean INL decreases with temperature increase.