Prototype the BGA

[Bill Shen]

While in my garage rummaging, I found this prototype board I built back in 1999.  BGA package became available around mid 1990's, but pc board layout tools, fabrication and assembly technologies were lagging behind.  Everything about BGA was expensive (except the BGA itself), so there were great deals of reluctance using BGA at the time, but there were some cool CPU only available in BGA package such as the PowerPC555 for automotive application.  The BGA pitch was fairly generous so it is conceivable to prototype it.  I did, and this was the MPC555 prototype.  It worked, but nothing came out of it.   The pitch of the BGA is 1.27mm so it was actually not too difficult to solder to it.  Of course I was 20 years younger then and before major eye surgeries to both eyes.  I actually did some cool works last century...

  Bill

PS, the prototype PC board shop was APCircuits in Canada and they are still in business.  At the time the 2-layer pc board had no solder mask nor silk screen and cost around $20 per board.  That was dirt cheap at the time.

[Richard Lewis]

Pretty cool how you deadbugged a BGA. BGA is the only SMT I've stayed away from. I've managed to hand-solder SSOP-8 with 0.5mm pitch but that's about my limit. 

[Duncan Reed]

With SMTs you just need a bigger microscope to go to smaller pitch, but BGAs are a different kettle of solder. You can see whats going on under there (not many hobbiests have an x-ray machine). Over in the Acorn (6502) groups a board has just been done with a BGA due to tight size constraints, replacing a no longer available custom chip. But the general consensus is to get them manufactured as in the long run cheaper than people messing up expensive BGAs.

[Bill Shen]

With BGA fabrication/assembly technology so mature 20 years later, prototyping the BGA is no longer necessary.  On the other hand, older BGA parts can frequently acquired very inexpensively, so it may be fun to purchase a lot of BGA and experiment with them such as this:
https://hackaday.io/project/36309-melting-the-balls-off-the-dragonball

  Bill