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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

    First, a minor correction. it is not correct to say "perform hierarchical RCX with the Hierarchy Editor". It is not possible to do hierarchical RC extraction using the Hierarchical Editor (HE). It is meant for controlling the views to use for simulation netlisting, not parasitic extraction. Parasitic extraction can only be done using QRC parasitic extractor. I think you meant to say "perform mixed views simulation with the Hierarchy Editor".

    You can do it as follows:
    a. Do hierarchical Assura LVS for layout cell "A" with ?preserveCells avParameters option. The cell file should contain B1, B2, C1, C2, C3, C4, C5 & C6
    b. Do hierarchical parasitic extraction with "excluded nets proper" option using QRC. Except for the required nets (e.g. C5-C6), exclude all other nets for RC extraction
    c. Create testbench schematic "myTB" with cell A in it
    d. Create a config view for "myTB" using HE
    e. In HE, set views of A, B2, C5 and C6 as "av_extracted"
    f. Do simulation using config view in ADE-L or ADE-XL

    This should give you what you want. : )  It takes a bit of time to exclude the unwanted nets but there is no choice because hierarchical extraction only works with "excluded nets" and "excluded nets proper" options.

    "excluded nets" option gives you R for the non-excluded nets and C on all nets. "excluded nets proper" options gives you RC on only the non-excluded nets. Please refer to $QRC_HOME/doc/qrcxUser/qrcxUser.pdf for more details.

    Best regards
    Quek

Reply

  • Hi Jimito13

    First, a minor correction. it is not correct to say "perform hierarchical RCX with the Hierarchy Editor". It is not possible to do hierarchical RC extraction using the Hierarchical Editor (HE). It is meant for controlling the views to use for simulation netlisting, not parasitic extraction. Parasitic extraction can only be done using QRC parasitic extractor. I think you meant to say "perform mixed views simulation with the Hierarchy Editor".

    You can do it as follows:
    a. Do hierarchical Assura LVS for layout cell "A" with ?preserveCells avParameters option. The cell file should contain B1, B2, C1, C2, C3, C4, C5 & C6
    b. Do hierarchical parasitic extraction with "excluded nets proper" option using QRC. Except for the required nets (e.g. C5-C6), exclude all other nets for RC extraction
    c. Create testbench schematic "myTB" with cell A in it
    d. Create a config view for "myTB" using HE
    e. In HE, set views of A, B2, C5 and C6 as "av_extracted"
    f. Do simulation using config view in ADE-L or ADE-XL

    This should give you what you want. : )  It takes a bit of time to exclude the unwanted nets but there is no choice because hierarchical extraction only works with "excluded nets" and "excluded nets proper" options.

    "excluded nets" option gives you R for the non-excluded nets and C on all nets. "excluded nets proper" options gives you RC on only the non-excluded nets. Please refer to $QRC_HOME/doc/qrcxUser/qrcxUser.pdf for more details.

    Best regards
    Quek

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