METHOD OF CALIBRATING A THERMOMETER-CODE SAR A/D CONVERTER AND THERMOMETER-CODE SAR-A/D CONVERTER IMPLEMENTING SAID METHOD

摘要

The present disclosure relates to a method of calibrating a thermometer-code SAR-A/D converter, said thermometer-code SAR-A/D converter comprising a N bit -bit digital-to-analog converter (DAC) for outputting a N bit -bit output code, said digital-to-analog converter (DAC) comprising a first subconverter (C MSB ) having a plurality of N Th thermometer elements T j (1) and a second subconverter (C LSB ) having a plurality of N Bin binary-weighted elements (2), wherein said N bit output code is equal to the sum of N BitTh and N BitBin where N Th = 2^N BitTh and N BitBin is equal to N Bin = N BitBin . The calibration method includes the steps of determining (5) an Integral Non-Linearity error value (µ R ) of a R th thermometer-code level of said thermometer elements T j according to the formula: µ R = ˆ‘ j = 0 R - 1 E j - R N th ˆ‘ j = 0 N th - 1 E j where E j represents the relative differences between said plurality of thermometer elements T j and a reference thermometer element T ref selected from said plurality of thermometer elements T j of said digital-to-analog converter (DAC) - minimizing (6) the maximum of said error value µ R to obtain a minimized error value; - generating (7) said output code (OUTPUT) according to said minimized error.