I have custom transistor compact models that have what amounts to a fail flag. The flag establishes a certain type of behavior for that one transistor when set to one. I would like to be able to set that flag in one single transistor instance in an arbitrarily large hierarchical structure without having it propagate to other instances of identical cells. For example:
I have a top-level schematic view myinverters that contains three inverters wired in series, all of schematic cellview inv1 and they are named I0, I1, and I2. Within inv1 there is a pmosfet and a nmosfet. If I descend into inv1 and modify the fail flag in the pmosfet it will set that flag for all instances of inv1. What I want is a SKILL based approach that will, for example, set only the pmosfet fail flag in I0 and not propagate to instances I1 and I2.
Does a mechanism exist for this type of operation and if so could I get a push in the right direction? A kludgy way would be for me to build a data structure for the hierarchy, find all the fet instances, identify the parent cell, create a copy, modify the one transistor, rebuild the schematic, and simulate from there but I'm hoping for something simpler and more native. I should add that ultimately the goal is, via SKILL, to iterate through all fets in the design (of a known model type), simulating each case, and building a results table of the impact of the fail flag on each.