Although ratioed logic has some attractive qualities, the majority of digital circuits are built using CMOS. CMOS is extremely versatile, robust, and pervasive. Its noise margins and signal integrity properties allow it to be reliably used where no other logic family would survive. CMOS also has some of the best power dissipation behaviors available, totally eliminating static power. However, CMOS gates observe magnified external loading, leading to important challenges in obtaining high-speed performance.