Mechanical Discussion 9/20/2017 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 Mounting Variants Straddle Mount Small/Large Right Angle (RA) Small/Large

Module Versions Small w/ Latch 2x QSFP Large w/ Latch 4x SFP 4x RJ45 Connector 1 Connector 2 Mating Force Unmating Force Small Size 4C + OCP Bay NA 64N (6.5kg) (14lbs) 20N (2kg) (4.5lbs) Large Size 2C 96N (9.8kg) (21.6lbs) 30N (3kg) (6.7lbs) 4x RJ45

Top/Bottom Component Placement Sizing Details Available Space PCB Size Top/Bottom Component Placement Routing Inner Layers Small Size 74x115 70x109 Large Size 118x115 114x109 2mm card guide keep out - 4mm to width (card guide) - 6mm to length (edge connector) 2mm card guide keep out Requests/Updates Length has been updated to 115mm Due to tight layout of SFP and RJ45 we propose to increase the width 2mm (to 76mm and 120mm) In regards to the above form factors. Is this enough usable space for expected configurations?

RJ45 Issues Availability of low profile 1x4 RJ45 connectors is a risk. Most designs are above 12mm tall which exceed our maximum height of 11.5mm. Centering the RJ45 connector vertically on the faceplate would be ideal; this would require sink-mount RJ45 with 9.5-10mm of height. Need community feedback on RJ45 configurations required to see if connector vendors can support. 1.4mm gap **View shown includes 8.8mm Pulse sink-mount elevated to the ideal height**

EMI Shielding Option 1 Option 2 Finger Stock Option 1 Finger Stock Die Cut Gasket Option 2 Finger Stock Finger stock used top and bottom is the most reliable method, with more rigid faceplate. Uses slightly more vertical internal chassis space due to upper internal flange. Die cut gasket (270 degrees) and bottom finger stock is more risky due to very thin 2mm tall gasket across the top. Faceplate is less rigid, uses the same vertical space as first option but outside the chassis. **Both options included in 3D CAD for evaluation**

Straddle Mount Small/Large Vertical Stack-up Straddle Mount Small/Large Right Angle (RA) Small/Large

Next Steps Community mechanical questionnaire – please provide detailed feedback Close on – Keep outs, board size, stack up heights, EMI shielding, connector options Considering ¼ turn fastener in place of thumb screws Will be in Dallas for OCP workshop

3D CAD Notes Option 1 EMI Shielding - Hide circled items