Metastability
Example
- input changes at 1 MHz
- system clock of 10MHz, flipflop (tpd + tsetup) = 5ns MTBF = exp( 95ns / 1.5ns ) / ( .4s ??107 ??106 ) = 25 million years
- if we go to 20MHz then: MTBF = exp( 45ns / 1.5ns ) / ( .4s ??2?107 ??106 ) = 1.33 seconds!
Must do the calculations and allow enough time for synchronization