5 ms·

"Hand solderable" is a relative term. BGAs are often easier than soldering TQFPs.

by nutjob2 8y ago

moftz 8y ago
I'd rather throw a board in a reflow toaster oven than try to hand-solder that monstrosity.
deleted 8y ago
[deleted]
krastanov 8y ago
Really!? For me it is trivial to solder a TQFP chip (quite quickly with flux, but it is doable even without flux). On the other hand I do not trust myself to do BGA by hand placement (presumably with solder paste from a stencil and whether with heat gun or a reflow oven). Am I missing something?
- joezydeco 8y ago
  You're not. BGA is a pain in the ass, and unless you have an X-ray device to check solder integrity you're going to always be wondering if that last heat cycle took successfully or not.
  - crispyambulance 8y ago
    BGA with a sane pitch size and not too many balls is feasible with a basic reflow setup if you have boundary scan and functional testing. The guy who created tinyFPGA did it-- https://theamphour.com/395-an-interview-with-luke-valenty/ https://theamphour.com/395-an-interview-with-luke-valenty/ By the time you got more than 1 BGA in the BOM however, it's time to seriously consider an assembly service.
    - escherplex 8y ago
      Question for you: how much flexiblity is there in the connection points on these surface mount components? Unlike DIPs seems any heat expansion or mechanical flexing would break the connections.
      - crispyambulance 8y ago
        I don't think it's a matter of flexibility but rather rigidity. One of the products I work on has a BGA with over 1400 balls at a very fine pitch (smt done at contract manufacturer with serious machines, of course). The really high ball-count devices always go on thick multilayer PCB's (ours has 32 layers). Mechanical flexing certainly can break connections but that requires a significant force that "should never" been seen in the field. BTW, one way to troubleshoot for already existing poor connections on a BGA (other than using boundary scan) is to blast it with cold spray or push down on it while running a test. If it stops working or suddenly starts working, you know you have a problem. The cold-spray/heat-gun/press-down troubleshooting techniques won't hurt good connections. These things can be a pain in the ass, but a properly soldered BGA on an appropriate board with appropriate heat sinks and fixturing is very reliable-- they're everywhere.
toomanybeersies 8y ago
I haven't soldered in a while, but back when I did it for a living, I could've soldered that package entirely by hand in under a minute. Just flux, tack the corners, and then run a blob of solder down the leads. Super easy once you get the hang of it. It's amazing how good you get at tasks when you do them 8 hours a day.

"Hand solderable" is a relative term. BGAs are often easier than soldering TQFPs.

moftz 8y ago

I'd rather throw a board in a reflow toaster oven than try to hand-solder that monstrosity.

deleted 8y ago

[deleted]

krastanov 8y ago

Really!? For me it is trivial to solder a TQFP chip (quite quickly with flux, but it is doable even without flux). On the other hand I do not trust myself to do BGA by hand placement (presumably with solder paste from a stencil and whether with heat gun or a reflow oven). Am I missing something?

joezydeco 8y ago
You're not. BGA is a pain in the ass, and unless you have an X-ray device to check solder integrity you're going to always be wondering if that last heat cycle took successfully or not.
- crispyambulance 8y ago
  BGA with a sane pitch size and not too many balls is feasible with a basic reflow setup if you have boundary scan and functional testing. The guy who created tinyFPGA did it-- https://theamphour.com/395-an-interview-with-luke-valenty/ https://theamphour.com/395-an-interview-with-luke-valenty/ By the time you got more than 1 BGA in the BOM however, it's time to seriously consider an assembly service.
  - escherplex 8y ago
    Question for you: how much flexiblity is there in the connection points on these surface mount components? Unlike DIPs seems any heat expansion or mechanical flexing would break the connections.
    - crispyambulance 8y ago
      I don't think it's a matter of flexibility but rather rigidity. One of the products I work on has a BGA with over 1400 balls at a very fine pitch (smt done at contract manufacturer with serious machines, of course). The really high ball-count devices always go on thick multilayer PCB's (ours has 32 layers). Mechanical flexing certainly can break connections but that requires a significant force that "should never" been seen in the field. BTW, one way to troubleshoot for already existing poor connections on a BGA (other than using boundary scan) is to blast it with cold spray or push down on it while running a test. If it stops working or suddenly starts working, you know you have a problem. The cold-spray/heat-gun/press-down troubleshooting techniques won't hurt good connections. These things can be a pain in the ass, but a properly soldered BGA on an appropriate board with appropriate heat sinks and fixturing is very reliable-- they're everywhere.

toomanybeersies 8y ago

I haven't soldered in a while, but back when I did it for a living, I could've soldered that package entirely by hand in under a minute. Just flux, tack the corners, and then run a blob of solder down the leads. Super easy once you get the hang of it. It's amazing how good you get at tasks when you do them 8 hours a day.