Hi, I have another question, I want to put the constraint of 3 ns for the setup time. Is the following a right way to do? [QUOTE][QUOTE][QUOTE] set_input_delay -clock clk_ideal_one 3.0 [find -ports -input -no_clocks[/QUOTE][/QUOTE][/QUOTE] clk_in] <<< What does this command do during synthesis. Looking forward to hear from the experts. Thanks in advance.