Setup time
Beginner
How early the data must be ready before the clock tick so a memory cell grabs it correctly.
Novice
The minimum time the data at a flip-flop’s input must be steady before the clock tick that captures it. Data that arrives later than that may be stored wrongly. The setup check: launch arrival + data delay must be no later than period + capture arrival − setup time.
Expert
Stored in the Liberty library as a table indexed by the data and clock edge rates. The setup check pairs the slowest (late) data with the earliest possible capture clock, subtracts clock uncertainty, and adds back the common-path credit (CPPR).