Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

148-pin QFN case on 1 mm PCB

Hello, In its Cyclone 4 family Altera introduced new 148-pin QFN case. What is the reason to recommend rather thin PCB, <0.8 mm, for this case? Is it PCB thermal expansion? And what ca...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Hi HJS,

Thank you for the reference. Unfortunately I can not use a BGA, it's too large. There's absolutely no way to fit it into that PCB. And it is very difficult to make a complicated PCB, 0.8 mm thick in one area, 1.6 in another one.

So I'd be happy to know what is the problem exactly, is it just because of different PCB thermal expansion during assembly? If yes, is it reasonable to choose some other material for my PCB, rather than FR4?

Regards