Breaking News
Comments
Newest First | Oldest First | Threaded View
<<   <   Page 2 / 10   >   >>
BillWM
User Rank
Freelancer
Re: A Horripilation of Ball Grid Arrays
BillWM   9/26/2013 5:01:32 PM
NO RATINGS
The PQFP and similar packages are better for this but still have limits to the thermal cycling issue -- This can be partly addressed with underfills for All the different types of packages -- When thinking of the ROHS aspects to the underfill -- remember that half as many boards will need to be built -- providing a much bigger impact in this Aspect of Underfill vs No Underfill -- also not using the corner three balls enhances life by at least a factor of two -- with underfill and no corner BGA ball use one can get 5-10x the life out of a BGA in an aerospace application.

Max The Magnificent
User Rank
Blogger
Re: A Horripilation of Ball Grid Arrays
Max The Magnificent   9/26/2013 4:47:43 PM
NO RATINGS
@BillWM: ...(50-80G's)

Ah, much like driving with my mother (LOL)

BillWM
User Rank
Freelancer
Re: A Horripilation of Ball Grid Arrays
BillWM   9/26/2013 4:33:05 PM
NO RATINGS
The boards have to pass the shock test in all axis -- the columns will shear in two of the axis without the supporting mount. (50-80G's)

Max The Magnificent
User Rank
Blogger
Re: A Horripilation of Ball Grid Arrays
Max The Magnificent   9/26/2013 4:22:41 PM
NO RATINGS
@BillWM: The CGA's often require an IC mount that is around the peripheral of the board for high shock applications.  (Example hard landing with an aircraft)

Is this because the peripherly of the board is better supported, while the center tends to flex more?

(Can't we just ask the pilots to make softer landings? " :-)

BillWM
User Rank
Freelancer
Re: A Horripilation of Ball Grid Arrays
BillWM   9/26/2013 4:19:03 PM
NO RATINGS
The CGA's often require an IC mount that is around the peripheral of the device for high shock applications.  (Example hard landing with an aircraft)

Max The Magnificent
User Rank
Blogger
Re: A Horripilation of Ball Grid Arrays
Max The Magnificent   9/26/2013 2:34:42 PM
NO RATINGS
@betajet: Aren't there issues with maintaining column stiffness under stress?  :-)

They are formed from a stiffer mix in the middle and a softer (more meltable) mix at the ends. My understanding is that they are very rugged and reliable and are used in things like military applications.

betajet
User Rank
CEO
Re: A Horripilation of Ball Grid Arrays
betajet   9/26/2013 2:18:51 PM
NO RATINGS
I haven't had experience with column grid arrays.  I would think you'd still have the concern that solder doesn't flex as reliably as copper or aluminum.  Aren't there issues with maintaining column stiffness under stress?  :-)

Max The Magnificent
User Rank
Blogger
Re: A Horripilation of Ball Grid Arrays
Max The Magnificent   9/26/2013 10:03:16 AM
NO RATINGS
@betajet: My chief worry is stresses on the balls caused by thermal mis-match between a BGA package and its underlying PC board

Being a string man, I'm going to totally ignore the opertunity to make jokes about stresses on your balls due to thermal management and instead ask if you've had any experiance with column grid arrays (CGAs) in which the solder balls are replaces with solder columns that mitigate against thermal stress (much like wearing looser undergarments :-)

zeeglen
User Rank
Blogger
Re: A Hackery of Software Developers
zeeglen   9/25/2013 7:45:53 PM
NO RATINGS
Poking proctological fun at non-engineers:

A promise of politicians

A scourge of salesmen

A loathe of lawyers

A bill of doctors

A menagerie (or zoo) of managers

A butt of bosses

betajet
User Rank
CEO
Re: A Horripilation of Ball Grid Arrays
betajet   9/19/2013 6:46:28 PM
NO RATINGS
FYI: Disadvantages of BGAs.  My chief worry is stresses on the balls caused by thermal mis-match between a BGA package and its underlying PC board.  Those tiny solder balls don't flex like proper metal leads -- they crack.  And who knows whether those mechanical stresses are causing tin whiskers, since that phenomenon is not well understood.  "Oh my ears and whiskers!"

<<   <   Page 2 / 10   >   >>


EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Creating New Faceplates for Antique Analog Meters
Max Maxfield
40 comments
I've currently got a couple of hobby projects on the go that feature the use of antique analog meters. For example, there's my Inamorata Prognostication Engine and its companion, the ...

EDN Staff

11 Summer Vacation Spots for Engineers
EDN Staff
11 comments
This collection of places from technology history, museums, and modern marvels is a roadmap for an engineering adventure that will take you around the world. Here are just a few spots ...

Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
11 comments
- An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
45 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)