In electronic design automation (EDA), parasitic extraction (PEX) is calculation of the parasitic effects in both the designed devices and the required wiring interconnects of an electronic circuit: parasitic capacitances, parasitic resistances and parasitic inductances, commonly called parasitic devices, parasitic components, or simply parasitics.
The major purpose of parasitic extraction is to create an accurate analog model of the circuit, so that detailed simulations can emulate actual digital and analog circuit responses. Digital circuit responses are often used to populate databases for signal delay and loading calculation such as:
Analog circuits are often run in detailed test benches to indicate if the extra extracted parasitics will still allow the designed circuit to function.
On a typical semiconductor die you can categorize the parasitics in 3 categories:
There are two types of engines which can be used for parasitic extraction:
Fields Solver Based
In this method, the PEX engine solves Maxwell’s equations to calculate the parasitic R, C, L or K. This method is referred to as 3D extraction. It is a higher accuracy method than the rule-based method, but also takes more processing power and is not used for full-chip extraction. Within the field solver category, you could have finite element or random walk algorithm being employed – tradeoff being processing time vs. accuracy, finite element algorithm being more accurate.
Rule Based
In this method, the PEX engine uses a look up table to calculate the parasitic R or C. This method is referred to as 2D or 2.5D extraction. It can support full-chip extraction.
Synopsys offers parasitic extraction solutions for both digital and custom design environments: