Synchronizers and Data Flip-Flops are Different

Careful synchronizer design is imperative as System-on-Chip (SoC) products become prevalent in safety-critical applications. Previously, use of a flip-flop optimized for data applications was adequate for most synchronizer uses when laid out as a two-stage design. Increased demands for both reliability and low-power have exposed this two-stage solution to misuse. The recognition that a synchronizer should be optimized differently from a data flip-flop opens the design space to new approaches. Some examples are presented and two aides to the process are introduced.