ClockBoost

A clock multiplication feature available in ACEX^® 1K, APEX^™ 20K, APEX^™ II, ARM^®-based Excalibur^™, FLEX 10KE, and Mercury^™ devices that is used in conjunction with the ClockLock^® phase-locked loop feature. The ClockBoost^® feature can be used to generate internal clocks that operate at frequencies that are multiples of the frequency of the system clock. The ClockBoost feature also provides clock delay reduction.

You can take advantage of the ClockBoost feature by using the altclklock megafunction.