A method for characterizing an integrated circuit that includes ramping the supply voltage to an integrated circuit as a function of time for each of the transistors in the integrated circuit, and measuring a power supply current for the integrated circuit during the ramping of the power supply voltage. The measured peaks in the power supply current are a current pulse that identifies an operation state in which each of the transistors are in an on state. The peaks in the power supply current are compared to the reference peaks for the power supply current for a reference circuit having a same functionality as the integrated circuit to determine the integrated circuit's fitness.