Output delay constraints

Hi, Thanks for your reply.

system approach:

>> max : tsu + max data delay – min clk delay

>> min : - th + min data delay – max clk delay

I understand the data delay and clk delay depends on trace length, if the length are same,then Max delay=Tsu, Min Delay=Th?

skew approach:

>>however, if device has tsu/th requirement then you must use system approach.

I think, still we can use skew approach. Any idea of what the below formulae tends to express?

Max = (unit interval / 2) - maximum skew value.

Min = maximum skew value - (1.5 * unit interval).

Skew value is the setup time in max and hold time in min?