pico-teensy-teensy future?

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Not sure that is is the future for the market the Teensy aims at. We are reaching a practical size limit. The MICRO USB connector on the Teensy board is the second largest component. Paul had to go to a 4 layer board to get al the pins on the chip routed to the perimeter of the board and smaller than 0.1" breadboards are not vey common and are also at he lowest practical size limit. Human hands and dexterity have their limits. I can hand-solder 0402 resistors, but 0201 is getting to be ridiculously small. Human hands and dexterity have their limits.

It is a interesting article for designers that use these chips in products in fully integrated packaging. Reflowing BGA chips, at home also approaches the limit of practicality rather rapidly.
 
These parts require very advanced PCB process. At a minimum, filled micro-vias are needed.

I do not know of any PCB fab companies that do this at the relatively low volumes PJRC would buy. Then again, I haven't really looked very much either.
 
Headroom said:
It is a interesting article for designers that use these chips in products in fully integrated packaging. Reflowing BGA chips, at home also approaches the limit of practicality rather rapidly.
Click to expand...
But end users wouldn't solder/work with any components on the board - just as we don't (?) alter ICs or passives on the Teensy boards. Interconnect off-board - maybe that goes RF or wired serial?
 
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Well, you may not, but there are serval users here on the board that have bought the Mini54 and have integrated the microprocessor into their own board. I've contemplated about it for a future project.
Also it is not unusual for BGA packages to require a 6-8 layer board due to the desisty of the connections.
 
With BGA at 0.8 mm or larger pitch (the center-to-center distance between the balls), vias are placed between each 4 balls to allow the interior signals to "escape".

But with very fine pitch BGA, you simply can't fit vias between the pads. They're just too close together. To use these BGA chips, you need a special PCB fabrication that allows vias in the pads. Apparently a fabrication step is added to fill the via holes with material that prevents the solder paste from flowing down the hole when the PCB is reflow soldered. None of the PCB fabrication companies PJRC has used offer this filled via option.

The via sizes also become extremely small. At 0.4 mm pitch, those BGA pads are about 7 mil diameter. My understanding is that's too small for an ordinary drilled hole. Instead, you need laser cut micro vias, which adds yet another expensive step to the PCB fabrication.
 
Yeah... this trend is futuristic. I suppose Freescale is promoting this for something.. like IoTs in the millions.
 
This is the wave for very high volume production, like cellphones. There are many of these type packages in the current iPhones. So think a prototype run of 10K units, while RasbPi has gotten close to those kind of numbers, you aren't going to see this in the hobbyist space.
 
And I must admit, I am not itching to move to even smaller packaging. Frankly, I don't care that cell phones, etc. have such smaller packaging and are cramming ever more processor power in the chips. If it is much smaller, I as an amateur, particularly one that is still bad at soldering through hole stuff, would have no way of playing in the field, doing simple little programs.
 
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