Dynamic synchronizer flip-flop performance in FinFET technologies

Abstract

The use of fine-grain Dynamic Voltage and Frequency Scaling (DVFS) has increased the number of distinct clock domains on a given Network-on-Chip (NoC). This necessitates robust synchronizers to prevent clock domain communication failures, even as FinFET devices have begun to replace planar devices. This paper presents simulation results and comparisons between dynamic (requiring reset) and non-dynamic synchronizer flip-flops implemented in predictive models for both planar technologies and future FinFET technologies. Results demonstrate that synchronizers built with FinFET devices 1) exhibit a tau value which continues to scale with fan-out of four delay and 2) can be improved with forward biasing, but 3) are more sensitive to temperature. Dynamic flip-flops settled metastability fastest when using standard technology voltages, but previously couldn't be used in non-dynamic systems. For this reason, a new synchronizer design is also presented which exploits the benefits of dynamic flip-flops without the need for a dedicated reset signal.