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Sweeping one parameter in only one test for ADE XL

NickSJ1196

Hello all,

I am looking to run two tests in ADE XL. One test has both transient and DC analyses, and the other is running an AC analysis to measure the input capacitance of a transistor. These analyses are separated in two tests because I am measuring the input capacitance via an RC constant and for the AC test, I set the resistor to 1 giga-ohm, while for the DC and transient tests the resistor must be set to zero to get accurate results. For my AC analysis, I would also like to measure pole at three different input voltages, to see how the input capacitance changes over the range. When I separate the design variables from the global variables in ADE XL, I can set them independently for the two tests, but I cannot do sweeps on ADE XL. Does anyone know how I can run the AC analysis at three different DC input biases without needing to run them in the DC/transient test that I have? Any help would be appreciated. Thank you!

Best,

Nick

  • Nick,

    You should switch to using ADE Assembler instead of ADE XL. ADE XL is past end-of-sale and ADE Assembler allows you to sweep design variables separately in each test (amongst many other enhancements over XL).

    Andrew

  • Dear NickSJ1196,

    NickSJ1196 said:
    One test has both transient and DC analyses, and the other is running an AC analysis to measure the input capacitance of a transistor. These analyses are separated in two tests because I am measuring the input capacitance via an RC constant and for the AC test, I set the resistor to 1 giga-ohm, while for the DC and transient tests the resistor must be set to zero to get accurate results.

    This may not be something you feel is possible, but did you consider using an AC resistor? You can set the AC resistance value of an analogLib resistor that is distinct from its DC or transient resistor value.  Hence, in your case, you will set its ac resistance to 1e12 ohms and its DC/transient value to a near zero value (for example, 1 milliohm). I think you can then use a single test.

    NickSJ1196 said:
    and the other is running an AC analysis to measure the input capacitance of a transistor.
    NickSJ1196 said:
    Does anyone know how I can run the AC analysis at three different DC input biases without needing to run them in the DC/transient test that I have?

    If you are measuring the capacitance, I assume you have chosen a specific frequency for your analysis. In that case, choose that frequency for the AC analysis and, in lieu of sweeping frequency, sweep the DC input bias in the AC simulation GUI (Figure 1). Hence, your AC simulation will be the only simulation where the DC input bias will be swept.

    I hope I understood your concern and this sparks an idea or two for you NickSJ11196,

    Shawn

    Figure 1

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