Recommended pads for UBGA-169

I think this is what you're looking for. This covers all BGA packages:

https://www.altera.com/en_us/pdfs/literature/an/an114.pdf

This document should be linked under the "PCB and Stack-Up Design Considerations" heading on the documentation page for whatever device you're using. For example, here's the link for Arria 10:

https://www.altera.com/support/support-resources/support-centers/board-design-guidelines.html#pcb-and-stack-up-design-considerations

Thanks,

Noam