How come in the pdf of the vq100 diagram, it shows something with 64 pins. This is odd because the spartan 3e sure doesn't come in a vq64, it comes in a vq100. Maybe they mean the vq100 has 64 pins but that doesn't make sense because the pinout spreadsheet has 100 entries. And how would you divide 100 by 4 to fill up 4 sides of a square chip? You cant do that with 100 unless its a 5 sided chip.
Thanks.
This is the link the datasheet sends you to.
This is the mechanical drawing for the xilinx VQ44, VQ64 and VQ100 packages, not limited to spartan 3e.
The pins drawn are just an indication and there happen to be 64 of them on the drawing, but that could have been 4 or 16 or 44...
Just use the sizes from the table for the VQ100 package. There are 25 pins on each side, symetrical around the center of the package, 0.5mm pin pitch. But with any luck there will be a suitable shape in your pcb package library.
I couldn't swear to it, but I think that 100 divided by 4 is close to
John
It makes more sense to me to have 5 sides than an odd number of pins one side
Hmm, why not make chip packages round? Would make soldering a bit more easy since the pin spacing would be maximal at the end of the leads.
Why do we have to be locked into the concept of a flat chip that has to rest on a flat board? I want spherical chips that snap together like playing legos.
Tell that to a 7400.
- Brian
Three horroble mistakes were made, that we suffer from to this day: dip packages are physically symmetric; pins are numbered circularly; Vcc and ground are in the corners.
John
Well, you are from outer space.
John
... except for the 7490. Which was probably an even worse mistake than the original corner power pinning, just from the surprise factor.
- Brian
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