This Paper Presents a Functionaldesign and Modeling of a Successive Approximation Analog-To-Digital Converter(Adc) and Its Application In the Conditioning Circuit of the Vibration Energyharvester. the Paper Published on Bmas’09 Highlighted the Necessity of a Smartdigital Control to Calibrate the System, Which Requires In Turn an Ultra Lowpower Supplied Adc. the Harvester and the Adc Are Designed Using a Cmos 0.35Μmhigh Voltage Technology and Modeled In a Mixed Vhdl-Ams/Eldo Environment. Thesupply Voltage of the Adc Is 2.5V. the Whole System Was Simulated Using a Mixedsignal Advance Ms Simulator.