Stats

  • Locked Locked
  • Replies 24
  • Subscribers 128
  • Views 16691
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

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

  • It does not mean that lvs will be executed only on B1, B2, C1, C2 and C3. It means that during lvs, only cells B1, B2, C1, C2 and C3 will be preserved. During lvs, cells might sometimes be promoted to a higher level of hierarchy in order to match the schematic. As such, the cell will no longer be present in the final lvs database. This would create a problem for hierarchical QRC extraction because QRC works on the lvs database and if there are no cells in it, it would not be possible to do a hierarchical extraction. QRC normally gives a flat output unless hierarchical extraction is selected.

    Hence in order to do QRC hierarchical extraction, the cells have to be present in the lvs database and in order to ensure that they are present, we use ?preserveCells option. You should not enter C4, C5 and C6 in the Exclude box because we want them to be preseved too. Otherwise you will not get the full cell hierarchy from QRC. C4, C5 and C6 should also be entered in the Cells box. You can then choose to use "av_extracted" or "schematic" for these cells in the Hierarchy Editor.

    Best regards
    Quek

Reply

  • It does not mean that lvs will be executed only on B1, B2, C1, C2 and C3. It means that during lvs, only cells B1, B2, C1, C2 and C3 will be preserved. During lvs, cells might sometimes be promoted to a higher level of hierarchy in order to match the schematic. As such, the cell will no longer be present in the final lvs database. This would create a problem for hierarchical QRC extraction because QRC works on the lvs database and if there are no cells in it, it would not be possible to do a hierarchical extraction. QRC normally gives a flat output unless hierarchical extraction is selected.

    Hence in order to do QRC hierarchical extraction, the cells have to be present in the lvs database and in order to ensure that they are present, we use ?preserveCells option. You should not enter C4, C5 and C6 in the Exclude box because we want them to be preseved too. Otherwise you will not get the full cell hierarchy from QRC. C4, C5 and C6 should also be entered in the Cells box. You can then choose to use "av_extracted" or "schematic" for these cells in the Hierarchy Editor.

    Best regards
    Quek

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.