the setup time is related to the specific application if the setup time refers to the chip, but if the setup time refers to the design of the chip, as is answered above.
Set up time and hold time are important timing parameters in digital components having clock and data together. In these components data must constant for some times, the time which data must be constant before the active clock pulse is called set up time and the time which data must stable after the active clock is called hold time.
All circuit components take some time for processing the input and plotting the out put usually called time delays. In the processing time of input the data must me constant; it may either logic HIGH or LOW. Other wise we will not get required out put.
set up time is the time that input(s) must be stable befor clock edge comming.
it is estimated by worst case of skewed time of clock and rise slop (or fall slop) of clock.
for moe information see timing of flip-flop
http://en.wikipedia.org/wiki/Flip-flop_(electronics)
setup time and hold time are two parameters considered in the timing of devices.
for example in flipflops the timing of the response of a flipflop to input data and clock must be taken into consideration when using edge-triggered flipflops.there is a minimun time called setup time for which the input must be maintained at a constant value prior to the occurrence of the clock transition.