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  3. Problem: Input impedance simulation of chopping amplifi...

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Problem: Input impedance simulation of chopping amplifier

zhanghao
zhanghao over 9 years ago

For my design of chooping amplifier, a postive feedback loop has been added to boost impedence. When I do the input impedence simulation by PSP, ZM is shown as following. . The results is very strange because he value decended in low frequency. As all known, the impedence should be higher in lower frequency. I cann't understand the reason. So I wonder if it is rightI the usage of ZM in PSP simulation. I also find the method of calculating the impedence like   

And I do the calculation in Cadence, the result is , the value is so minimum than that in the  PSP simulation. So I wonder that the input impedence of amplifier is simulated or  calculated in cadence, which is right? I appreciate it for your any suggestion.

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  • Andrew Beckett
    Andrew Beckett over 9 years ago

    The pictures are missing, you didn't mention the versions used, and it's not clear what your simulation setup is (maybe that's clear in the invisible pictures). So I don't think it's possible to help based on the very limited information above, unfortunately.

    Kind Regards,

    Andrew

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  • Andrew Beckett
    Andrew Beckett over 9 years ago

    The pictures are missing, you didn't mention the versions used, and it's not clear what your simulation setup is (maybe that's clear in the invisible pictures). So I don't think it's possible to help based on the very limited information above, unfortunately.

    Kind Regards,

    Andrew

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