The Anomalous Behavior of Flip-Flops in Synchronizer Circuits

Quantitative results of the observations of oscillatory and metastable behavior of common flip-flops in response to logically undefined input conditions, such as those that occur in synchronizers and arbiters, are presented. The results are obtained with the help of a circuit developed for this purpose which measures the failure rate for a certain flip-flop and frequency. It is found that the obtained results are in good correlation with observed failure rates of a synchronizer with both short and long flip-flop resolution times allowed.