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ke4pjw wrote: »
I am very excited to see this! Looking at the bonding image, it has a date of 2014. Is that a typo, or did the actual bonding not change since that was proposed?
Can't wait to play with the P2 :)
KeithE wrote: »
Chip - is there a simple test that you could do to check the pinout before mounting the chips? e.g. carefully check some power and ground pins with a multimeter? If there's any asymmetry in the pinout then perhaps something simple can be done. I remember once when something similar happened to us with a WLBGA (wafer level BGA) chip, but it was easy to check because you could see the die ;-)
cgracey wrote: »
Man, I hope this all works.
Beau Schwabe wrote: »
Hope you have a steady hand ... soldering that fine pitch can be tricky, even with a stencil and re-flow oven. You might need all 4 of those PCB boards just to get one good one out of the bunch. ...or at least past a slight learning curve. We made a Compact Flash adapter card with the same pitch I believe of 50 pins at .5mm and even with a microscope and a soldering iron it was a challenge to make sure there weren't any solder bridges.
Understanding Solder surface tension is your friend ... Sometimes counter intuitively using more solder is better than using less solder in a situation like this.
Roadster wrote: »
That board looks like it was designed with ExpessPcb, I hope the test chip works, I will have my fingers and toes crossed
Tubular wrote: »
Exciting stuff, Chip
Its a minor point, but since we're testing analog - you have a ground loop caused by that track underneath and two ground entry points along the left hand header. What i'd do is make your top left the single ground entry point, and put a test pin before the ground goes to the 1v8 regulator, for connecting cro's and logic analyzers etc. Connect both ground pins at top left (technically a ground loop but only 0.1"). Disconnect the ground connection at bottom left of the header, or break it with a 0.1" jumper if you really think you might need it for current purposes. Break the ground connection where it leaves the regulator tab, then route a solid ground from the test point at top left to underneath the chip, and connect to the existing ground networks using several vias.
Hope this makes sense.
Rayman wrote: »
But, eventually, I got at stencil reflow oven and that made it much, much easier.
Also, having a microscope or something like it helps a lot.
The solder joints come out disgustingly perfect