Assura RCX: coupled and decoupled extraction

[wccheng]

assura rcx manual

Dear all,

I have seen the manual of the Assua Physical Verification User Guide. However, I am still not clear what is the different between the coupled and decoupled parasitic caps. extraction. Could anyone explain it in detail? Thanks for your helping.

Best Regards,

wccheng

 

[srivatsan]

assura rcx

Can I get the copy of the manual, please? Thanks.

- Srivats

 

[maxwellequ]

assura manual

Imagine that node "n1" has parasitic capacitances to nodes n2, n3, n4 and GND, as follows:
n1->n2 : 2 fF
n1->n3 : 10 fF
n1->n4 : 1.5 fF
n1->GND: 5fF

The output netlist in the "coupled" mode will be
C1 n1 n2 2f
C2 n1 n3 10f
C3 n1 n4 1.5f
C4 n1 GND 5fF

In the "decoupled" mode, the capacitances of a certain node are added together and placed between it and GND. For the example above:
C1 n1 GND 18.5f

(18.5=2+10+1.5+5)

This can make the simulation run faster, but it might be dangerous since the crosstalk between nets is not simulated.

Rgds