A flip-flop operating with standard threshold voltage MOS devices as compared with high threshold voltage MOS devices may have improved speed performance, but greater leakage current. Likewise, a flip-flop operating with high threshold voltage MOS devices may reduce the leakage current and have better power efficiency, but decreased speed and performance. An optimized flip-flop may include a combination of standard threshold voltage MOS devices and high threshold voltage MOS devices. The optimized flip-flop may have less leakage during stand-by mode as compared to a flip-flop with standard threshold voltage MOS devices. In addition, the optimized flip-flop may have better performance and speed as compared to a flip-flop with high threshold voltage MOS devices.