Macro Placement Guidelines

Macro Placement Guidelines

After Pin placement, we place macros in the design keeping in mind below rules:

One thing I am sure that if you read the below points carefully, you will be able to easily place macros for any complex blocks.

Distance between macros = (No. of Pins * pitch *2) / Available metal Layers

1. Macros should be placed at the periphery of the block.
2. Interacting Macros should be placed near to each other which is also known as logical grouping.
3. Macros should be placed by taking care of channel optimization to avoid criss-cross placement of Macros. Placement should be done in proper multiple of tracks so that macros can be routed properly.
4. Avoid placement of Macros or stacks near the ports in order to avoid congestion in later stages of physical design.
5. Placement of macros should happen in a way so that Macro pins face towards core to avoid detour.
6. Placement of macros should be done in simple rectangular shapes to avoid area loss.
7. After macro placement, we need to place halos around the Macros to avoid congestion around the macros.
8. Try to put hard blockages or partial blockages in the area where there are gaps in between Macros.
9. Try to avoid notches while placement of macros.
10. There should be minimum gap between the Macros.
11. We should allow channels for routing pins and for buffer insertion which helps during timing optimization while placing possible required buffer.
12. Check for all the macros if they are in power domain fence.

NOTE: Before Macro placement, we should look for the fly lines which helps us in giving directions for proper placement of Macros.

Macro Placement Guidelines in Physical Design VLSI
Gaurav Sharma
Gaurav Sharma

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