aviation PCB footprint standards

[v_kumar]

pcb footprint sizes

HI,
I heard from one of my friends that in the PCB boards used in Planes the footprint should be made with minimal pad size and other constraints.

my question is that are there any stands for these type of boards if so can anyone upload the same.

Thanx

 

[cyberrat]

pcb footprints standards

Minimal pad sizes?

Hmm, I heard that in planes they prefer to use pad sizes that can handle the g-force (bigger?) if its for a jet.

 

[touringmike]

ipc-2221 footprint

It's been over 15 years since I've worked in Military stuff (which included Aircraft design), back then we used Mil Standards ,Mil-275D specifically for PCB design, and it was anything but minimal. Military standards required 10 percent spares of everything, meaning if you had 100 14 pin Dip packages on a design, you needed 10 spare devices, with each pin routed to 2 pads for manual wiring purposes.

This standard has now migrated to the jursidiction of IPC standards, IPC-275D in this instance, as Mil Standards have been pushed down to the industry supported standards.

 

[v_kumar]

pcb footprints document

can anyone uplod the standards or pm

 

[sb4141]

ipc-275d

hello

im lookin to start an industry in the field of electronics may be pcb manyf/assembly or something! what would be ideal.. wud prefer cnc.... market and for it cost?? plz suggest...

 

[palladin69]

The primary goal for aviation/aerospace is reliability. We design to IPC 2221 series documents, and always as Class 3.
The first step is to design a footprint with lands/pads that will give you the best solder joint you can get. Then it is up to your assembly process, if you have a lot of through-hole, you may want larger pads if it is going through wave. You can have smaller pads with reflow and vapor phase and get good fillets on your solder joints.
The new footprint standard - IPC-7351 - has provisions for least-nominal-maximum pad sizes. Based on your design, board density, assembly processes, you have determine what will give you the highest reliability.
The board designer"s job is determining which tradeoffs give you the most reliable assembled product possible.
I like the old Mil standard (275) and the old IPC standards (275, 279, 780, 782) because I started with those, but the information is in the new docs also; I just had to learn to look for it in a different location.

 

[v_kumar]

but for aviation i have heard that when the gravitationl force decreases and surface density increases than the pads will come out that is why you should go for minimum pad size

does anyone has any document which relates this..
if so than please upload or PM me.