Transition Time vs Propagation delay -> which one is bigger?

[ivlsi]

Hi All,

As for the Transition Time and Propagation delays, which one is usually bigger/critical?

Thank you!

 

[rca]

Re: Transition Time vs Propagation delay -> which one is bigger?

That is really dependent of the technology node.

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Do you have a case?

 

[ivlsi]

Re: Transition Time vs Propagation delay -> which one is bigger?

Hm... What's the situation in the 25nm and 45nm nodes?

Do you have a case?

I just was recently told by someone that the transition delays usually take the significant part in the signals propagation through the nets / cells... Just wanted to check it up ...

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Is it possible to separate between transition and propagation delays using STA tools (using SPICE I guess it's possible) ?

 

[rca]

In any timing report you could know the part due by the trans, the net delay, the cell delay.

 

[hoanglongroyal]

hi ivlsi,
I really have no much experience in that case, but I guess: trans seem be less than propagation delay. as I saw in 65nm technology with NLDM lib : propagation > 2xtrans (ofcourse for output trans of the same cell/pin relate/condition/....)

 

[rca]

why you did not used CCCS model instead NLDM? less accurate no?

 

[hoanglongroyal]

hm... this just a case. I don't think have big difference in ccs model.