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stb Ocean/Skill examples

dlbro

Does anyone have any examples of using the stability analysis (stb) Sprectre tool in Ocean/Skill? I've done extensive scripting in transient, AC, DC, noise, pnoise, etc... but this is the first time I've tried stb. Running stb is easy, I've seen some stuff on how to do phase margin and gain margin, but how do I plot the gain and the phase? I've searched Cadence and Source link and the internet to no avail. Is there any equivalent to VT(), VF(), VS() for stb?

Thanks in advance,

dlb

Parents

  • Thanks Andrew,

    I wasn't able to figure out either method you suggested. For the first one, when I double click on the waveform it brings up the "Trace Attributes" form which doesn't have any SKILL expressions. Also, I can't see any way to save an Ocean script from the ADE.

    But, your suggestions pointed me to a different solution. If you pull up the result browser and select the stb-stb category it has the loopGain result, if you select this and then hit the calculator button you get:

         getData("loopGain" ?result "stb-stb")

    Then to plot the data just stick this in a phase() or db20() function:

        phase(getData("loopGain" ?result "stb-stb"))

        db20(getData("loopGain" ?result "stb-stb"))

    To get the phase margin, phase margin frequency, gain margin and gain margin frequency use:

         getData("phaseMargin" ?result "stb-margin.stb")

        getData("phaseMarginFreq" ?result "stb-margin.stb")

        getData("gainMargin" ?result "stb-margin.stb")

        getData("gainMarginFreq" ?result "stb-margin.stb")

    Thanks for the getting me unstuck.

    Dave Broughton

Reply

  • Thanks Andrew,

    I wasn't able to figure out either method you suggested. For the first one, when I double click on the waveform it brings up the "Trace Attributes" form which doesn't have any SKILL expressions. Also, I can't see any way to save an Ocean script from the ADE.

    But, your suggestions pointed me to a different solution. If you pull up the result browser and select the stb-stb category it has the loopGain result, if you select this and then hit the calculator button you get:

         getData("loopGain" ?result "stb-stb")

    Then to plot the data just stick this in a phase() or db20() function:

        phase(getData("loopGain" ?result "stb-stb"))

        db20(getData("loopGain" ?result "stb-stb"))

    To get the phase margin, phase margin frequency, gain margin and gain margin frequency use:

         getData("phaseMargin" ?result "stb-margin.stb")

        getData("phaseMarginFreq" ?result "stb-margin.stb")

        getData("gainMargin" ?result "stb-margin.stb")

        getData("gainMarginFreq" ?result "stb-margin.stb")

    Thanks for the getting me unstuck.

    Dave Broughton

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