Path Requirement - 2025.2 English - UG906

The path requirement is the time difference between the capture edge and the launch edge of a timing path.

Using the same clocks and path as in the previous section, the setup path requirements are as follows:

Setup Path Requirement (S1) = 1*T(clk1) - 0*T(clk0) = 4ns
Setup Path Requirement (S2) = 2*T(clk1) - 1*T(clk0) = 2ns

The corresponding hold path requirements are as follows:

• For setup S1:

  Hold Path Requirement (H1a) = (1-1)*T(clk1) - 0*T(clk0) = 0ns
  Hold Path Requirement (H1b) = 1*T(clk1) - (0+1)*T(clk0) = -2ns

• For setup S2:

  Hold Path Requirement (H2a) = (2-1)*T(clk1) - 1*T(clk0) = -2ns
  Hold Path Requirement (H2b) = 2*T(clk1) - (1+1)*T(clk0) = -4ns

Timing analysis uses only the two most pessimistic path requirements. In this example, the most pessimistic paths are as follows:

• Setup requirement S2
• Hold requirement H1a