An enhanced method for characterizing successive approximation converters

A strategy for characterizing successive approximation, analog-to-digital converters with quad current switch architectures is described. It permits detailed parameter specification (accuracy and linearity) without recourse to testing every transition voltage. The results show an encouraging reduction in the residual error from 0.144 step (from a currently used test) to 0.048 step with the proposed test for the specific case of 12-b converters. To achieve this result, only 2.6% of the transition voltages require measurement. The percentage of codes to be tested reduces dramatically as the number of bits of the converter increases. The evolution of the proposed test is investigated by examining the cause and effect of superposition errors. >