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Altera_Forum's avatar
Altera_Forum
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17 years ago

Clock Uncertainity

Hello All,

Consider a FF1-Comb-FF2 circuit, both flops clocked by same clock clk1.

If clock frequency of clk1 is 16 ns, Comb delay is 0 ns, FF set up time is 0.2 ns and Clock uncertainity is 0.5 ns,

1. What will be max operating freq of this system. ?

2. Will clock unceratainity be used in max freq calculation ?

Plz share your thoughts,

regards,

freak

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Hi,

    The classic timing analyser uses this equation for Fmax:

    fmax = 1/(register to register delay - clock delay + micro tsu + micro tco)

    As to clock uncertainty, I believe I should add it to Tco