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Cheers,

I try to make my own pcb :-) Details will follow but here the first facts:

• Main PCB will get µATX, ATX or E-ATX form factor
• Main PSR is default ATX PSR mounted in 19" server rack which the main pcb will be mounted
• BFL Chips will be solder on carrier PCB in one of actual CPU Socket form factor (e.g. LGA1155). They will get an copper heat spread on top mounted.
• Every Carrier can handle one to max 7 chips (maybe 8 depends on needed adress for PSRs)
• On Main PCB CPU sockets will be mounted to connect the BFL carrier and a proper CPU cooler solution
• Every BFL will get there own (maybe programmable) psr (which needs one own SPI address for psr controller) with sense lines as near as possible to the chips
• Option for external clock is planned (maybe need one more SPI address).
• BFL Chip Controller solution is selectable: AVR or Rasberry Pi (or other)
• Temperature will be measure by internal chip temp sensor
• KiCad will be used for planning the layout and design.
• The design files will be shared.

Ready:

• Documentation from BFL stored
• BFL Chips ordered and fully payed
• KiCad installed.
• BFL Chip symbol created for KiCad

Next Steps:

• Generate simple layout for carrier pcb
• Generate simple layout for main pcb
• Create chips to socket netlist
• Select psr module solution

Open questions:

• Documentation from BFL described Done signals in daisy chain mode. On SC Board instead chip done signals are directly connected to AVR. Why?
• What are the possible heat spread sizes for different LGA sockets? In fact also what are the dimensions of different cpu's?
• How much CPU sockets can be used on main pbc?
• Maybe because of large size 2 Layer board could be used for main pcb.
• Is the Rasberry Pi strong enough?
• When will I get my BFL chip order in hand? In 1st week of october as promised?
• How much are the costs of the more expensive parts?

My recent favorites:

• 8 BFL on LPGA-2011 Carrier with copper heat spread because of needed min. die size 42mm x 42 mm
• 8 PowerOne DP8120 POL controlled by DM7308 Power controller
• Rasberry Pi as Controlller with SPI Mode for controlling BFL Chips
• Fallback PSR DeltaOne D12S050201C with trim

References:

• BFL Chip description page https://forums.butterflylabs.com/announcements/3014-butterfly-labs-announces-bulk-chip-sales.html
• BFL Chip description link https://forums.butterflylabs.com/attachments/announcements/1321d1371338930-butterfly-labs-announces-bulk-chip-sales-bfl-sha2-spec-rev2.2-release.pdf
• Delta Electronics D12S050201C 20A DC/DC POL http://www.delta.com.tw/product/ps/dcdc/std/download/data_sheet/DS_D12S05020_10282008.pdf (http://www.delta.com.tw/product/ps/dcdc/std/download/data_sheet/DS_D12S05020_10282008.pdf)(Cheap and easy for one chip)
• PowerOne ZY1120 20A DC/DC POL http://www.power-one.com/sites/power-one.com/files/zy1120.pdf (http://www.power-one.com/sites/power-one.com/files/zy1120.pdf)(Expensive still easy to use, parallel configuration possible)
• PowerOne DP8120 20A DC/DC POL Digital http://www.power-one.com/sites/power-one.com/files/documents/power/datasheet/dp8120_data_sheet_1r0.pdf (http://www.power-one.com/sites/power-one.com/files/documents/power/datasheet/dp8120_data_sheet_1r0.pdf)(Programmable by DM7300G Power Controller)
• PowerOne DM7300G Power controller http://www.power-one.com/sites/power-one.com/files/documents/power/datasheet/dm7300_datasheet_rev_1r0.pdf (http://www.power-one.com/sites/power-one.com/files/documents/power/datasheet/dm7300_datasheet_rev_1r0.pdf)(Power controller for PowerOne POL series)

To be continued.