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 DC Sweep of a DFF 

Last post Sat, Sep 1 2012 2:46 PM by Eshar. 1 replies.
Started by canbaltaci 27 Aug 2012 03:56 AM. Topic has 1 replies and 734 views
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  • Mon, Aug 27 2012 3:56 AM

    DC Sweep of a DFF Reply

    I am making a DC sweep for the CLK input of a DFF. However, I am not able to see the desired clk-to-output (Q) characteristics since I do not know how to set the output value to "1" or "0" at the first sweep value (i.e. the output value of the sim is not a stable operating point at initially).

    How can I see the transfer characteristics in such a simulation? Is there a way to set the initial values for DC sweep?


    Best regards,


    • Post Points: 20
  • Sat, Sep 1 2012 2:46 PM

    • Eshar
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    • Joined on Sat, May 12 2012
    • Posts 14
    • Points 205
    Re: DC Sweep of a DFF Reply

    You can set the initial condition for a node in the circuit. Search for initial conditions in the spectre manual or whatever simulator you are using.

    However, it doesn't make sense to do it for a DC sweep since DC doesn't simulate the dynamic characteristics of a circuit. I am guessing you are looking for which clock voltage will cause the output to change. You could set the output initial voltage and run a transient simulation with the clock input being supplied with a slow ("nearly DC") voltage ramp. It just needs to be much slower than the clk-to-q time.

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Started by canbaltaci at 27 Aug 2012 03:56 AM. Topic has 1 replies.