@User: Go ahead and assume that you use VDDA2 = 7V and VSSA2 = -5V. The power supply pads on the padframe will need to be decoupled from the voltage clamps; we can swap in the appropriate padframe layout if you have the correct alternative pads and connections in the top-level verilog. Use the power pad from sky130_fd_io without the overlay and without making connections to the clamp in that cell, and you should have a simple direct connection between core and pad. But I think that configuration still has pad diodes, which would not work with either voltage; especially the -5V will clearly forward-bias the pad diode to VSSIO, and I don't think +7V is going to be okay on the VDDIO diodes, either. I'm sure a solution is doable, I'll just have to investigate how to break down one of the power pads into simpler subcircuits that don't have the diodes or clamps.