90nm process & SI & cross-talk

[ivlsi]

Hello All,

As for the 90nm process, are the Signal Integrity and Cross-Talk timing checks necessary?

When should I decide that SI is necessary for my design?

Thank you!

 

[rca]

You could enable the SI checks for all techno nodes. You will in your reports the differences with or without SI. Below 180nm, I run with SI mode to be sure for the worst path.

 

[ivlsi]

Thank you rca,

What does it mean "enable the SI checks"? What should I do in my Synthesis and STA scripts for that?

You will see in your reports the differences with or without SI

What does it mean? Can I generate reports with and without SI considerations? Are there special commands for that?

Thank you!

 

[oratie]

First of all, during the RC extraction you should enable 'coupling capacitance' extraction (it means, thar RC extraction tool will calculate capacitance between neighbouring wires, rather than lump it to ground). Then, in PrimeTime you may use command report_noise (see manual for this command, because it may require some variables/parameters to be set).

 

[rca]

in PnR or STA tool, you could enable the SI mode.
take care the SI mode calculation is not necessary the same in all tools, then you could not have the exact timing tool to tool.

 

[ivlsi]

you could enable the SI mode

What does it mean exactly? What exactly should I do besides reading the spef file and using 'report_noise' command?
Is there a command-line switch or another directive, which "say" to the tool consider "cross-talk" coupling?
Thank you!

---------- Post added at 22:51 ---------- Previous post was at 22:44 ----------

What additional files (besides SDF & Netlist) do I need for the crass-talk checks? What additional checks should I perform for SI?
Thank you!

 

[matter]

Hi Dmitryl,
You keep asking what exact commands/variables to use, but you have not mentioned which tool you are using inorder to tell you exactly the commands/settings necessary to enable SI analysis. Please be specific.
Assuming that you are using Synopsys Primetime, the setting that you need to use is
set si_enable_analysis true

Yes, you can generate timing reports with and without SI effects. If you do a "set si_enable_analysis false" and run then run report_timing, you will get timing reports without SI effects.

Different tools will have different variables that need to be set. If you are using cadence, there will be some other similar variable which I don't know. I believe that the specific settings for SI analysis are clearly mentioned in Primetime User Guide, so please read it. Likewise I think that other EDA tools will also have similar user guides, so please go through them as there will be a few other filter settings that you need to understand to get good results. You can also use in built man pages for the other xtalk/filter settings.

 

[ivlsi]

yes, when I asked my questions, I kept in my mind the PrimeTime...
The reason I've asked for the relevant commands and settings was so I wanted to get the relevant info from the people who have experience with the tool (besides reading the formal Synopsys guides). Hopefully you agree with me that Synopsys and other EDA companies write their guides in such way that engineers should require courses and trainings after reading them... Anyway, thank you for your post!

 

[matter]

Hopefully you agree with me that Synopsys and sometimes other EDA companies write their guides in such way that engineers will require courses and trainings after reading them...

Ya, that is true. Some of the user guides won't give you the full picture and you will need additional hands on training.