Abstract: D/A conversion network of SAR (SAR: Successive Approximation Register) ADC was discussed. The energy model of the capacitor array in R-C hybrid D/A network was established by using MATLAB. With the combination of resistor string’s static power and capacitor array’s switching power, the power model of the R-C hybrid network in SAR ADC was proposed based on a 65nm CMOS process. Furthermore, by considering matching requirement for the passive components, 12-bit R-C hybrid D/A networks with “5+7”, “6+6” and “7+5” type of structures were simulated and compared. The research can provide significant guidance for circuit design and optimization of low-power SAR ADC.

Key words: successive approximation register (SAR), D/A conversion network, energy model, low-power