Some good thoughts thanks.Stimpy wrote: ↑Tue Apr 03, 2018 9:35 pm Might be best to use the latest tools and latest series of cyclone, 4 or 5. Might cost a bit more but will give you more room to add things and the speed will be greater as the routing won't be so complex and they are made on a smaller die process. You also get nice things like DDR controllers, larger block ram etc. Also don't be put off by BGA as tqfp is dead for FPGAs, same goes for 5v logic levels. 1.0mm BGA is pretty easy to route and as you don't need much IO you can just use the outer connections and route straight out. You'll need decent decoupling as the edge rate on the IO drivers can be very fast so 0402 caps good idea.
I think myself and rodolphe did look at BGA a couple years ago.. but we had issues routing anything with them even on multilayer boards. So we kinda gave up and just stuck with TQFN.. Though like you say, with a lot of IO we would only need the outer pins.. so worth a look..
One problem I envision is TQFN is pretty large, and I have go to use IO converters as well yet. I want to try and keep it as small as possible overall.