Novel hybrid D/A structures for high-resolution SAR ADCs—analysis, modeling and realization

An intermittent-sleeping C–R hybrid D/A structure, a resistor-reusing R–C hybrid D/A structure and an R–C–R combined D/A structure are researched with theoretical analysis and Matlab modeling in this paper. The switching power and passive components' matching requirement of these D/A structures are discussed in detail. Three SAR ADCs with these three novel structures are realized based on SMIC 0.18 μm CMOS, SMIC 90 nm CMOS and UMC 90 nm CMOS, respectively. The theoretical analysis, modeling verification and circuit realization proves the applicability of these three D/A conversion networks to high-resolution SAR ADCs.