Changing the package doesn't mean they changed the chip itself. If you look at the pin-outs on major chips you'll see a lot of them are redundant, extra power lines and stuff like that. I think they use a lot of lines because the connecting lines are so thin - I would imagine putting a high load on an individual line would damage the chip, so they have a bunch of lines to spread out the power load.
The package they're using has space for extra pins, that doesn't mean they're actually going to be connected to anything, or aren't just going to be used as extra power lines.
What? If they change pad-balls they change chip, or have had a design error. Prefer to be a chip change that an error.
Not to sound a troll, I am buyer KNC.
Who says they changed the number of pads? The balls might not be connected to anything at all. I'm not a semiconductor engineer - but the number of balls isn't necessarily 1-1 with the number of pads on the IC. (oh, and there are
cool videos of wire bonding on youtube, you can see how tiny the connecting wires are, they couldn't individually carry a lot of current so you need a lot of lines to carry 250 watts)
If you have a 55^2mm package, it may be simpler just to cover the bottom of the package with balls rather then have a custom stencil made or whatever.
Or, finally it may simply be that the diagram is incorrect and there will be missing balls on the actual chip. Once you get your miner you can take it apart, heat up the chip and remove it and count the balls if you want.
Basically I wouldn't worry that much about the discrepancy, although you could ask them for input since we're all curious.
Wow! Thats a lot of solder balls per chip. Is this amount of connections normally soldered reliably in manufacturing?
The way it works, they just set the chip on the board, and heat it up enough for the balls to melt. If you search "bga reball" on youtube there are videos of people taking the chips off and putting them back on at home. Once you put the balls back on the chip, you just have to set it on the board and heat it up for the balls to melt, IIRC.