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  3. How to simulate the stability of a fully differential amplifier...

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How to simulate the stability of a fully differential amplifier using the iprobe?

xxgenerall
xxgenerall over 11 years ago

The schematic is as follows. 

It is very useful tool used to simulate amplifiers' stability. Well, when simulating a fully differential amplifier, how to use the iprobe?

Thanks in advance. 

  • diffAmp.jpg
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  • Andrew Beckett
    Andrew Beckett over 11 years ago

    If using and old version like this, you can use cmdmprobe from analogLib instead. This has been replaced by diffstbprobe in later releases, since that is an improved way of measuring the common mode and differential mode stability in a way that can handle "unbalanced" loops - i.e. where  you have significant common mode to differential mode (or vice versa) gain. The cmdmprobe is fine for balanced differential loops, where both halves are the same.

    The implementation of cmdmprobe is essentially the same as the netlist  you've provided, but the UI understands how to probe the correct iprobe inside the cmdmprobe.

    Regards,

    Andrew.

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  • Andrew Beckett
    Andrew Beckett over 11 years ago

    If using and old version like this, you can use cmdmprobe from analogLib instead. This has been replaced by diffstbprobe in later releases, since that is an improved way of measuring the common mode and differential mode stability in a way that can handle "unbalanced" loops - i.e. where  you have significant common mode to differential mode (or vice versa) gain. The cmdmprobe is fine for balanced differential loops, where both halves are the same.

    The implementation of cmdmprobe is essentially the same as the netlist  you've provided, but the UI understands how to probe the correct iprobe inside the cmdmprobe.

    Regards,

    Andrew.

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