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    Optimized MinCap, Minres values for 10 MHz amp simulation using Spectre

    Hi I try to do post-layout simulation using spectre.
    Because the entire chip size is very large, the calibre cell size extracted PEX is also large.
    So i want to set the Minres and Mincap value to reduce the number of parasitic elements.
    Please give me a guide how to choose appropriate Mincap and Minres for 10 MHz analog IC simulation.
    Thank you.

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    Re: Optimized MinCap, Minres values for 10 MHz amp simulation using Spectre

    Due to very probable serial connection of RC elements I'd calculate with the 10-fold frequency, hence 100MHz. So I'd try e.g. with mincap=100fF and minres=16Ω (f = 1/2πRC).



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    Re: Optimized MinCap, Minres values for 10 MHz amp simulation using Spectre

    As I know next to minres and mincap there is a maxbandwidth option to throw away the too small R-C pairs. If you don't want to use it share a bit more please, what is your circuit, why 10MHz, why RC PEX you are using, etc.
    "Try SCE to AUX." /John Aaron/



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    Re: Optimized MinCap, Minres values for 10 MHz amp simulation using Spectre

    You should be very careful with parameters like minres and mincap - read the manual, how extraction tool you are using handling them.

    For example, minres can cause extraction tool to "drop" (short) small parasitic resistors.
    In the example above, all resistors below 16 Ohm are shorted.
    Your point to point resistances will not be preserved, after such operation.

    mincap can "decouple" small parasitic capacitances between the nets - so instead of capacitive coupling between two nets, you may see capacitances to ground from each of the (originally) coupled nets.

    Familiarize yourself with these parameters, and inspect teh results carefully, in order to avoid unpleasant surprises.



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