README_fab.txt

Marble board
Dual FMC FPGA carrier board developed for general purpose use in particle accelerator electronics instrumentation.

https://github.com/BerkeleyLab/Marble

This packet contains the usual manufacturing files for both
PCB fabrication and turn-key assembly:
Gerber, Drill, IPC-D-356, Board stackup, BoM, and X-Y placement.

The design is created in, and these manufacturing files are mostly
exported from, KiCad version 6.0.11.

This is a 12-layer, 1.72mm (nominal) board.  Materials and thicknesses
according to the board stackup description:
  marble-stack.txt

Three heat sinks are called out in the BOM and shown on the schematic:
  HS1  for U1 FPGA
  HS2  for U35 Power Supply
  H23  for U2 Clock Mux
The latter two are stick-on.  HS1 is special: it clips on,
but requires thermal grease applied between it and the FPGA.
The hope is that the person assembling it is practiced with heat sinks,
understands the importance of thermal grease, and has a tube on their shelf.
Dow 340 seems to be the general-issue grease these days, but any known-good
thermal grease is acceptable.

Design rules are 0.10 mm space, 0.10 mm trace, 0.152 mm drill
(0.35mm pad).  The overall board size is 150 mm x 180 mm,
similar to the AMC double-width standard.

- PCB Material: FR4
- Soldermask color: Black
- Silkscreen color: White
- Copper weight for inner layers is 0.5 oz and for outer layers is 1oz + 0.5oz = 1.5oz

The SI conversion of the traditional PCB industry unit "1 oz" (really ounce/square-foot)
is 305.15 g/m^2.  That _might_ convert to 34.15 micrometers layer thickness,
but only if the copper plating has the density of pure bulk material at 20 C,

Copper Gerber files, in order:
  marble-F_Cu.gbr
  marble-In1_Cu.gbr
  marble-In2_Cu.gbr
  marble-In3_Cu.gbr
  marble-In4_Cu.gbr
  marble-In5_Cu.gbr
  marble-In6_Cu.gbr
  marble-In7_Cu.gbr
  marble-In8_Cu.gbr
  marble-In9_Cu.gbr
  marble-In10_Cu.gbr
  marble-In11_Cu.gbr
  marble-B_Cu.gbr

Silkscreen, soldermask, and solderpaste files
for front and back:
  marble-F_Mask.gbr
  marble-F_Paste.gbr
  marble-F_SilkS.gbr
  marble-B_Mask.gbr
  marble-B_Paste.gbr
  marble-B_SilkS.gbr

The board mechanical outline is given by:
  marble-Edge_Cuts.gbr

Drill files, plated-through and non-plated-through:
  marble-PTH.drl
  marble-NPTH.drl

Bill-of-material, X-Y placement, and IPC-D-356 files:
  marble-bom.csv
  marble-xy.pos
  marble-ipc-d-356.txt

Two more oddball files, not used for fab:
  testpoint_map.gbr
  testpoint_map.gvp
They are there to produce a PDF that might help troublehsooting:
gerbv -p testpoint_map.gvp -x pdf -o testpoint_map.pdf

SHA-256 signature file, which can be used to verify the integrity
and version of all of the files listed above:
  marble-sha256.txt
That file's SHA-256 signature, in turn, is found at the end of
this README file.