Comparison of D-flip-flops and D-latches: influence on SET susceptibility of the clock distribution network

As technology scales down, clock distribution networks (CDNs) in integrated circuits (ICs) are becoming increasingly sensitive to single-event transients (SETs). The SET occurring in the CDN can even lead to failure of the entire circuit system. Understanding the factors that influence the SET sensitivity of the CDN is crucial to achieving radiation hardening of the CDN and realizing the design of highly reliable ICs. In this paper, the influences of different sequential elements (D-flip-flops and D-latches, the two most commonly used sequential elements in modern synchronous digital systems) on the SET susceptibility of the CDN were quantitatively studied. Electrical simulation and heavy ion experiment results reveal that the CDN-SET-induced incorrect latching is much more likely to occur in DFF and DFF-based designs. This can supply guidelines for the design of IC with high reliability.