Question about Structural WLM

[ivlsi]

Hi,

Here is a definition of the Structural WLM: "It's based on the information about neighboring nets rather than just fanout and module size information".

So, the Structural WLM is also a Statistical one, but takes in account the interfaces as well? How does the neighboring nets may affect the WLM?

Thank you!

 

[birdy123]

Re: [WLM] Structural WLM

hi,

For that you should know why WLM is used. refer this..
https://vlsi-expert.blogspot.in/2011/09/delay-interconnect-delay-models-static.html

Wire load models is used to calculate the delay .. so what are the different factors effecting the delay-- Capacitance and Resistance.
Now there are 2 type os capacitance .. Surface capacitance and Coupling Capacitance..
refer this
https://vlsi-expert.blogspot.in/2012/02/parasitic-interconnect-corner-rc-corner.html

So in the WLM .. the Capicatance value is the total capicatance.. and that's the reason Neighboring nets effects the WLM.

Hope this will help you.

 

[ivlsi]

Hi,

As for the Custom WLM, is this just RC extraction or building a real WLM tables like it appears in *.lib file?

Thank you!