Thinking about the floorplan for a layout, I plan on making some kind of grid to route power. Maybe horizontal rails that alternate between VSS and VDD on M3 and vertical rails that alternate between VSS and VDD on M4. Someone I know recommended that I connect the four corners of this power/ground grid to the nearest pins to avoid IR drop. With this in mind, is it advisable/possible to use the regular IO pads as power pads? My design only operates at a VDD of 1.8V. Thanks in advance.

Knowing the resistance of each layer, you can easily calculate your IR drop. I would not suggest using regular I/O pads as power pads. They are not designed for that and do not have the proper clamping to protect against ESD events. Use

vccd1

or

vccd2

supplies (

vssd1

and

vssd2

ground returns) for 1.8V supplies, as these are properly equipped with clamps. You can also use

vdda1

and

vdda2

; although they have high voltage (3.3V nominally) clamps, they should work for 1.8V input. You can connect to both

1

and

2

to double up the number of pads you have for the supply.

Thank you @Tim Edwards