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Spectre: possible to use netlists for subcircuits in ONLY selected blocks?

dontpanic
dontpanic over 5 years ago

Hi! Is it possible to instruct Spectre to use netlists for subcircuits in only some blocks of a hierarchy, and other views (e.g. schematic) elsewhere?

Our foundry supplies netlists with extracted parasitics ("LPE netlists") for standard cells, and I can make Spectre use those (instead of the schematic views) if I specify so in the Hierarchy Editor  (config view). However, this can only be done for *all* the instances of a given cell, irrespective of location in the hierarchy, which results in unnecessarily long simulations as the LPE netlists are then also used for the standard cells in non-timing-critical blocks. Instead, I'd like to enforce the LPE netlists for just the cells in timing-critical blocks. Is this somehow possible?

Note that even though the "tree-view" mode in the Hierarchy Editor would seem to enable such enforcement, when simulating the resulting config view Spectre aborts because of finding multiple definitions for the standard cells ("[...] a subcircuit with the same name has been defined [...]" error).

I even tried making a copy of the standard cell library where I deleted all the schematic views, and use this lib (+the LPE netlists) for the cells in the timing critical blocks, but Spectre still cannot resolve the difference as the subcircuit names are the same for the cells in this and the original library (I guess I could rename the cells too, but this would then involve a lot of work for replacing all the instances in the all timing-critical blocks, so I disregarded it as a solution for not being practical).

(In desperation, I also tried to somehow use the MTS option in Assembler to this purpose, but it clearly seems not intended for such usage... or is it so?).

Thanks and regards, Jorge.

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