Wednesday, October 28, 2015

How to calculate minimum spacing between two macros?

Distance between macros can be known from = ( number of pins of macros * pitch *2) / number of available routing layers


or

Generally space between macros are calculated distance = ( number of pins * pitch ) / (total number of available metals/2)

why we are dividing with 2 means ... vertical and horizontal metals so we are dividing.

For example:
We have 2 macros having the pins of 100 each macro and pitch=025 and available metals are 6.
then space between 2 macros = ( ( 100+100)*0.25/(6/2)   This distance you should provide between macros.



How we find the number of pins?

Select the macro and press "q". It will give property of that macro.  Check " No. of terminals" in that.



16 comments:

  1. Pitch=0.25, its a pitch of which metal?
    During this calculation pitch of which metal layer we have to give?

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  2. If we are using rectilinear macros ..how to calculate spacing b/w them ?

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  3. I want to write a tcl script to find the distance distance between two macros ,if it is less than 10 micron I need to apply blockage there.

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    Replies
    1. You can do this using finish floorplan in Innovus, there this option is provided

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  4. This comment has been removed by the author.

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  5. The pitch is 0.25.
    How can we say the pitch? If the macro pins has 3 metal layers at that time how can we take pitch value?

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    Replies
    1. we are considering the worse case here, so considering the pitch which is amallest of the routing resources available, should be the correct way to go.

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    2. sir, it will affect the higher layer pitch because it has a more pitch than lower metal so there is small space for higher metal.
      please explain this concept again

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  6. Should we maintain the distance between the macros not to increase three times the height of the standard cell?

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  7. if pitch of each metal layer is different then how we consider the pitch value?

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  8. ex. m1=p, m2= 2p, m3= 4p then which pitch consider?

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    Replies
    1. In that ca se we can abutt macros in floorplan stage and we can find required spacing in placement stage by the congestion we are getting I guess

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  9. In this case, both macros are facing their pins with each other that's why we added 100+100 right?

    And what if we want to give vertical spacing and both the macros pins are different? We will consider the worst case, right?

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