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Hierarchical Parasitic Extraction & Cadence Tools

jimito13

Hello Everyone,

I have come up with a question and i would really want to hear the opinion of more expert people in here about my issue concerning parasitic extraction in an hierarchical design.So,let me pose my question more clearly :

I have an hierarcical design.Let's say that the top level schematic's name is A.

A consists of two sub-cells that i will give them the name B1,B2.

B1 has 6 more sub-cells (C1,C2,C3,C4,C5,C6).

I know hot to perform hierarchical RCX with the Hierarchy Editor tool of Cadence but...if i want to take into account the parasitics of the interconnections of some specific sub-cells what is the way to implement the extraction procedure and take correct results?Can Hierarchy Editor do this or i need another tool of cadence and subsequently an extra license for this?

A testbench for me in the hierarchy editor would be :

A -->Schematic

B1 -->Schematic

C1,C2,C3,C4 -->Schematic

C5,C6 --> av_extracted

B2 -->av_extracted

and i want to extract as well the interconnections between C5-C6 cells and between B1-B2 cells.I should note that all sub-cells have their own physical implementation (layout view in other words).

Thanks in advance for any helpful answer.

My Best Regards,

Jimito13

 

Parents

  • Hi Jimito13

    I think Andrew has already explained the key point. You will get whatever that is in the view which you have set in HE. We have the following situation:

    Top cell C contains 2 cells A and B. In HE, cell A uses schematic view and B uses av_extracted view. C is a schematic.

    Since C is a schematic, there are no parasitics in the line connecting cells A and B. Simulator does not need to be concerned about this situation because this is the job of the netlister. Here is what you will get:

    a. Netlister writes connection between A and B as ideal connection
    b. It descends into schematic view of cell A and netlist the devices
    c. It descends into av_extracted view of cell B and netlist the devices and parasitic RCs

    Hope that this clears up your confusion. : )

    Best regards
    Quek

Reply

  • Hi Jimito13

    I think Andrew has already explained the key point. You will get whatever that is in the view which you have set in HE. We have the following situation:

    Top cell C contains 2 cells A and B. In HE, cell A uses schematic view and B uses av_extracted view. C is a schematic.

    Since C is a schematic, there are no parasitics in the line connecting cells A and B. Simulator does not need to be concerned about this situation because this is the job of the netlister. Here is what you will get:

    a. Netlister writes connection between A and B as ideal connection
    b. It descends into schematic view of cell A and netlist the devices
    c. It descends into av_extracted view of cell B and netlist the devices and parasitic RCs

    Hope that this clears up your confusion. : )

    Best regards
    Quek

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