How is IR drop analysis done?

[ravipati]

How is IR drop analysis done? What are various statistics available in reports?

 

[ljxpjpjljx]

Re: IR drop analysis

is your company's backend flow belong to yourself?

 

[useless_skew]

Re: IR drop analysis

Blastrail/Quartzrail can do the IR drop analysis. We are usually interested in the % of vdd/vss drop. Also there are other tools available from Synopsys and Cadence to do the IR drop analysis.

 

[itsmeteja]

Re: IR drop analysis

IR drop analysis is done using any of the following Power Analysis CAD tools ::

Sequence - Cooltime
Apache - Redhawk
Magma - Blastrail/Quartz rail
Synopsys - Prime rail

For this analysis you need to have certain inputs depending on the design stage you are in.
General inputs are techfile (Avanti flow) itf (synopsys flow) tech lef (cadence/magma flow)
standard cell /hard macros gdsii
.libs for std cells and sub blocks
timing constraints
design def
design verilog netlist
power budget if its estimates are known else provide activity factor of 0.3 which is definitely pessimistic number
saif or some simulation file for running dynamic analysis.
Signal spefs
and some other optional inputs like sub ckts for decap's and wellcap subckts for standard cells

After providing all these info you can perform static (resistive drop) or dynamic (instantaneous drop) analysis. Then you can analyze the drop numbers either in gui or in textual report.

If you are doing IR drop analysis for the first time, then you will be much more interested in the grid connectivity.A tool from sequence called coolcheck which can be used to analyze grid connectivity even you can invoke the cooltime tool if you have cool check licence. As in some places even the grid connectivity is not proper it might be masked by IR product, for such cases coolcheck tool will be much more useful.

If you are using magma quartz rail you need not provide all the inputs I had provided, you can just provide the volcano DB with constraints as it has inbuit extractor.

Thanks
Teja