A pseudo C-2C and CBW hybrid DAC structure used for SAR ADC

Abstract

A hybrid DAC structure combined with conventional binary-weighted (CBW) capacitive array and pseudo C-2C capacitive array is proposed in the paper. Causes for nonlinearity of the structure are analyzed, including the effects of parasitics and the deviation of the capacitor adjustment parameter. Analysis of the power consumption and nonlinearity of the hybrid structure is also presented. This structure reduces power consumption by up to 99.1% compared to the conventional one. The linearity degrades with the increase of the number of pseudo C-2C units.