How to P&R power/ground rings for a multi-voltage chip?

[iamchine]

For minimum area,how to do it?
1) P&R rings on top-metal round by round?
2) P&R rings on samel round position metal by metal?
3) P&R on top-metal(horizontal) and the next lower(vertical) metal with vias connection to form rings round by round?
Which one is the best? Or any other better way?
Thanks a lot!

BR,
iamchine

 

[flyankh]

hi

I don't understand your case,for I haven't seen any standard cells working at 2 or more voltage on the same time in one chip.Or your means that the digital part's voltage is different to the analog part?


Regards

flyankh

 

[iamchine]

Re: How to P&R power/ground rings for a multi-voltage ch

hi flyankh,
I mean that digital part's voltage is different from analog IPs' voltage.Though for single voltage supply system,there're at least two rings for power/ground.Somebody told me power/ground rings must be laid on top metal,but I don't think so.I've no layout experience b4.
Thank you!
BR,
iamchine

 

[flyankh]

Hi

I think your fullchip floorplan can be decided till the pad location is given .Because the power is from power pad
You can make a ring around digital part and another around analog part ,but it maybe use more area in your chip.The ring around analog part sometimes can be canceled and you can connect the power from pad on higher metal,but you must make sure that the IP can work well with the digital noise.

Regards

flyankh

 

[iamchine]

Thank you,flyankh.