Scan-Controlled Pulse Flip-Flops for Mobile Application Processors

Novel high-speed low-power pulse-based flip-flops having a pulse generator controlled by scan input and scan enable signals are presented. The proposed scheme enables the reduction of data-to-output delay by elimination of the MUX-scan logic from the setup time path of flip-flop, at the cost of a small power overhead. The comparison results using the 45 nm CMOS process indicate that the worst-case DQ delay of the proposed flip-flop is reduced by up to 59% while the energy-delay product is improved by up to 80% compared to the conventional master-slave flip-flop. The silicon results show that the new flip-flops function properly down to 0.62 V.