This work presents a photovoltaic(PV) energy harvesting system with fast maximum power point tracking (FMPPT) circuit that utilizes a 4-bit successive approximation register analog to digital converter (SAR ADC) suitable for solar cells. Solar Panel’s output power depends on the switch duty ratio of inductive-boost DC/DC converter. Usability of 4-bit/cycle SAR ADC to adjust duty ratio is proved through the measurement, using conventional Pulse width Modulation (PWM) boost converter. MATLAB Simulation is carried out to test the performance of the SAR MPPT algorithm for Solar PV system