Abstract:Setup time is an important technical parameter of edge flipflop, which plays a key role in the design of crossclock domain circuits and highspeed digital circuits. In this paper, a physical measurement method was introduced for the setup time of the integrated edge flipflop or the selfmade edge flipflop. By using the same pulse to act on the clock end and the input end of the flipflop respectively, and using the delayer to scan and adjust the pulse time delay of the two ports, the statistical error distribution curve of the flipflop was obtained, thus more accurate parameters of setup time were obtained. Measurement was performed on the integrated edge flipflop 74LS74 chip, and the accuracy of 1ps was realized.