This is being looked at as a possible SparkFun product, if people are interested. Please post to this thread both if it sounds like a great idea, or if you don’t think that there’s any advantage over existing products, like those for the Telit GM 862 Quad.
Is the simpler breakout board (on the bottom) smaller than the GM-862 (ie. overall length/width/height)?
Also, maybe the smaller breakout board could be adjusted to have castellated edges so the board could be soldered flush on to a main PCB, eliminating some height constraints. Just a thought.
Andrew02E:
Is the simpler breakout board (on the bottom) smaller than the GM-862 (ie. overall length/width/height)?
The smaller board pictured above is 61mm x 48mm, or if you prefer inches, it’s 2.4" x 1.9". The GM-862 Eval Board - 50 pin [found here is listed as 2.5" x 2.5", so yes this is smaller.
Andrew02E:
Also, maybe the smaller breakout board could be adjusted to have castellated edges so the board could be soldered flush on to a main PCB, eliminating some height constraints. Just a thought.
I don’t think that it has any particularly important additional function over the GM-862 Quad, although you should probably verify that with Telit’s documents:
trevorz:
It’s main advantage of which I am aware is that it’s cheaper.
If the 863 has at least the same capabilities, with possible added features, and is less expensive, then why doesn't Spark Fun replace the 862 with the 863 as a product?
As someone who has tried (and failed) to mount the GE863 on my own board, I would love to see a compact breakout board for this module. It’s an expensive part to be experimenting with.
I would love to see the SIM holder mounted on the compact version too, even if it’s not populated by default, since it has high-frequency lines and the GE863 is not very forgiving. It wouldn’t affect the board size very much either.
bretth:
As someone who has tried (and failed) to mount the GE863 on my own board, I would love to see a compact breakout board for this module. It’s an expensive part to be experimenting with.
Could you shed some light on your failure? Im interested to hear what you tried.
As far as an 863 breakout board goes, if you could get the PCB footprint smaller than the GM862 breakout, and make it lighter in weight, i would glady pay the extra cost for this breakout.
Sure thing… hopefully someone can benefit from my $150 mistake
I do lots of surface mount stuff (using my SMT solder/hot-air rework station), but this wasn’t an option for the BGA GE863 footprint. So I picked up a hotplate from Walmart and did some experimenting with some other boards/components to get proficient.
When it came time to mount the GE863, I ran into several probs:
Took a lot longer than it should… I suspect this is because the GE863 absorbs so much of the heat.
Although it’s BGA, it’s more like Solder BGA… the balls are solder, not solid balls, and the heat was not even enough to melt all solder balls so the board would sink down. Perhaps it had a different melting point than the solder paste I was using.
Very difficult to remove board from the hotplate without having the GE863 module slide around a bit. I probably should have taped it down better.
Eventually I had it placed, double checked for shorts, and powered up the module. I was able to send/receive AT commands, but:
The unit seemed to reboot (silently) every 10-30 seconds, even with a solid power supply.
The SIM interface wasn’t working 95% of the time. I got it go SIM READY a few times, but most of the time it reported SIM ERROR. I think it registered on the network once, although maybe that’s just my brain shedding a positive light on the experience
I suspect both of these were a result of overheating the module during reflow, since my prior rev of the circuit worked fine with the GM862. I wasn’t willing to blow another $150 to see if my 2nd attempt would be more successful.
In the end I had to respin the board again to meet some changing requirements, so I reverted back to the GM862.
IMHO, having the SIM holder on the expansion board makes a lot of sense, since it’s not an optional part of the system, and the Telit docs have some pretty clear/strict guidelines around the SIM holder.
I had a couple of GE-863s assembled to PCBs by a specialist assembly company. It was quite expensive because they don’t have proper round solder balls and they had to get a mini-stencil made so that they could apply solder paste. True BGA devices don’t need solder paste.
To the SFE guys: I realize you may not be willing to commit to anything at this point, but can you tell us if you’re learning towards producing a GE863 breakout board? I’d like to use this module in my next project, and the availability of such a board would probably influence my approach for at least the first few prototypes over the next 1-4 months.
If the answer is “yes” or “probably”, I’d be interested to know if the smaller form-factor board would have an integrated SIM holder (or footprint for one).
maokh:
interesting idea … much like some of the surface mount socket clamshells.
i suspect the cost of development/production in such low volumes would make it more expensive than the cost of the module.
regarding the cost problem, it's unfortunately true.
i was crazily thinking of [these when i first looked into it.
the other day i realised that really what would be ideal would be as you’ve suggested, like the springy contacts on a SIM card holder. i thought they could be DIY made with bent paperclips or semi-heavy-gauge wire…