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- 23rd March 2007, 08:44 #1

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## delay model?

can anyone help me out wat are delay models & difference between them??

wat is wire load model?

thnaks,

in advance

- 23rd March 2007, 08:44

- 23rd March 2007, 10:21 #2

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## Re: delay model?

Hi,

Wire load model is based on the parasitics of interconects, it is calculated for unit length of interconect. The parasitics are then derived based on its actual length, and delays are calculated from the parasitics. The Wire load model varies for different technology, and also on the thickness of interconect used in routing.

- 23rd March 2007, 10:21

- 23rd March 2007, 10:43 #3

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## Re: delay model?

delay model (or) Wire load model as it can be called is useful in estimating the net delays.

Delay models consisits of Lookup tables where in you have satisitical arrangement of Resisitance values for corresponding net fanout and capacitence values for corresponding net fanout.

wire load model also consisits of net fanout v/s area.

- 23rd March 2007, 10:43

- 23rd March 2007, 11:06 #4

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## Re: delay model?

thanks roy & satya??

on roy's discussion wire load& delay model are one & the same........correct me if am i wrong..

- 23rd March 2007, 12:09 #5
## delay model?

http://www.trilobyte.com/pdf/golson_snug99.pdf

here is a paper by steve golson on wireload model.

- 23rd March 2007, 22:24 #6

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## Re: delay model?

Wire Load Model is a set of tables:

netfanout v/s load

netfanout v/s resistance

netfaout v/s area.

These WLM are simple table look up models which

calculates load(capacitence),resistance, area, based on fanout.i.e., for a value of fanout we will have statistical values for reistance and load.

So timing tool will assume R and C based on Wire Load Model (WLM)

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