I'm trying to get my head around the various diode model cards on offer and the documentation seems a bit sparse. Is there somewhere I can look that can give me a rough idea of what role each is designed to play in sky130 designs?

Essentially they're just all the parasitic diode combinations like well to substrate or diffusion to well, etc.

I figured as much, but wanted to be cautious since i'm not particularly familiar with how this pdk is stuctured. just to confirm diode_2 in the hd standard cells is meant for parasitic devices inclusion and is not actually meant for use as a designed device?

The

diode_2

cells in the standard cell libraries are for antenna tie-downs.

Thanks! I figured, considering how they were being used, but again....i tend to be a bit over cautious