Mechanical Discussion 10/18/2017 Joshua Held, Mechanical Engineer, Facebook Yueming Li, Thermal Engineer, Facebook John Fernandes, Thermal Engineer, Facebook Jia Ning, Hardware Engineer, Facebook
NIC v3.0 Configuration Small NIC with Straddle Mount Straddle Connector Chassis Face MB NIC v3.0 Module Snap in card guides both sides Small NIC with Straddle Mount
Straddle Mount Small/Large 1 Mounting Variants Straddle Mount Small/Large 1 Right Angle (RA) Small/Large 1
Module Versions Small w/ Latch 2x QSFP Large 1 w/ Latch 4x SFP 4x RJ45 Connector 1 Connector 2 Mating Force Unmating Force Small Size 4C + OCP Bay NA 64N (6.5kgf) (14lbf) 20N (2kgf) (4.5lbf) Large Size 1 2C 96N (9.8kgf) (21.6lbf) 30N (3kgf) (6.7lbf) Large Size 2 4C 116N (11.8kgf) (26.1lbf) 37N (3.8kgf) (8.3lbf) 4x RJ45
Survey Results Requests/Updates Small form factor ports Large form factor ports Partner Top Side KO (mm) Bottom Side KO (mm) Using QSFP Heatsink EMI Concept QSFPs SFPs 1G RJ45 10G RJ45 Fastner Use large NIC A 11 Defer to NIC vendors No Spring Finger 2 2 or 4* 2 or 4 SCR or 1/4 Yes (x32) B 12.5/25* 2.67/2.0 4 Yes C 1.9 Not effective 4 or 8* 1/4 Maybe (x32) D 11.75 2.2 Latch/Ejct Yes (x24) Current Spec 11.5 ? SCR Latch/Ejct Considering x24 and x32 * indicates stretch goal 11.5mm 2mm Requests/Updates Received survey responses from four community members - still accepting surveys Current spec proposal can be seen above in the last row Focusing mechanical design on spring finger concept Due to strong feedback we are now considering two large size NICs - x24 and x32
Top/Bottom Component Placement Sizing Details Available Space PCB Size Top/Bottom Component Placement Routing Inner Layers Small Size 76x115 72x109 Large Size 1 120x115 116x109 Large Size 2 142x115 138x109 2mm card guide keep out - 4mm to width (card guide) - 6mm to length (edge connector) 2mm card guide keep out Requests/Updates Width has been increased to provide clearance to SFP and RJ45 by 2mm (to 76mm and 120mm) Added x32 Smart NIC - Large Size 2 In regards to the above form factors. Is this enough usable space for expected configurations?
RJ45 Issues Delta and Luxshare have 1x4 RJ45 sink mount designs available at 10mm height. These fit nicely within C-channel of the faceplates as desired. Need to verify that and 1x2’s are available in the same height. Working on some challenges grounding RJ45 housings to faceplate.
Straddle Mount Small/Large Vertical Stack-up Straddle Mount Small/Large Right Angle (RA) Small/Large
Next Steps Working on DFM review with vendors Continue concept development Please provide feedback on current spec configuration Continue to close on keep outs, board size, stack up heights, EMI shielding, connector options