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Standard Cell Metal‑1 Power Supply Examples |
IR Drop
- IR drop problem
- Power delivery
- chip illustration
- 1W core power
- 2W core power
- 15% power straps
- 1W 30% blocks
- 2W 30% RAM, 20% analog
- upper power straps
- reducing impact
- 1W power best
- 2W power best
- 1W best 30% blocks
- 2W best RAM, analog
- summary of method
- conclusions
- example 1
- example 2
Derivations
The parameter ps is the percentage of metal-1 used for the standard cell power supplies and depends on the layout style used.
The drawing of the vsclib standard cell template above shows a cell height of 72 lambda with each supply 8 lambda wide. The amount of metal‑1 used for the power supplies is then
| ps = | (8+8)⁄72 = 22.2% |
The Alliance sxlib standard cell template at the top right shows each supply at 12 lambda wide and a total cell height of 100 lambda. The metal‑1 power supply percentage is then
| ps = | (12+12)⁄100 = 24% |
The wsclib standard cell library on the right is 80 lambda tall with 12 lambda wide Vdd and Vss power rails. The metal‑1 percentage used for power supplies is then
| ps = | (12+12)⁄80 = 30% |
