Oct/07/2010Pixel PP0 opto replacement issues1 1 1 PP0 Opto Replacement Issues Philippe Grenier, Martin Kocian, Dave Nelson, Marco Oriunno, Su Dong, Charlie Young

SQP / PP0 / Opto Numerology Total 8 OSP and 8 ISP at each end. Each pair of OSP+ISP=78+42=120 modules max, served by 6+6+6=18 opto-boards Each opto-board serves 8 modules max and for a total of 288 opto-board slots (272 active boards) in the system Oct/07/2010Pixel PP0 opto replacement issues2 Assumed scope: Replace [opto-board + fiber ribbon] with [electrical repeater + twisted pairs] while the rest of SQP more or less intact. New Opto-box on IDEP at ~6m away from PP0.

Current Opto-board I/O Summary 80-pin J1 connector to PP0: 2 x 8 XCK Clock 2 x 8 DCI Cmd In 4 x 8 DTO Data out 2 VPIN (no longer needed) 2 VISET (no longer needed) 2 NTC 2 RST (no longer needed) 7 VVDC 1 VVDC-sense 8 GND 1 x 8 channel fiber ribbon for Cmd+clk 2 x 8 channel fiber ribbon for Data (B-board) Oct/07/2010Pixel PP0 opto replacement issues3 2 x 6.5 cm 2

Opto-electrical replacement options Cmd link Optobox->PP0 variations –Opto-box decode BPM, PP0 has LVDS repeater only. –PP0 includes BPM decoder and LVDS repeater. –PP0 pass through decoded Cmd data with no repeater. PP0 Electrical Transition Housing Variations –Electrical Transition Board: hosting LVDS repeaters to replace opto-board, constraint to use same PP0 flex and 80 pin connector; twisted pairs soldered to ETB. –No connector option: LVDS repeaters surface mount on PP0 flex; twisted pairs soldered to PP0. Too late, no time for PP0 flex redesign. Clk for each module separately from Opto-box (one clk pair per row fanout at PP0 impractical) Oct/07/2010Pixel PP0 opto replacement issues4

PP0 Electrical Transition Space Check Each Opto-board sized area of 2 x 6.5cm 2 (8 modules) needs to host LVDS repeaters for –8 Clk pairs –8 Cmd in pairs –16 Data out pairs  4 x 8-channel Bonn LVDS repeaters, each needs package footprint for ~40 pins (assume preference for soldering packaged chip over wire bonds). Each LVDS repeater has ~1x1cm 2 area for pin spacing>0.5mm.  Array of 64 solder pads for twisted wires also need to fit on the board. Using both top and bottom ? Radial profile also important Oct/07/2010Pixel PP0 opto replacement issues5

Twisted Pair Wire Volume Each Opto-board worth of 8 channels has 32 twisted pairs. Assuming AWG28 Cu-clad Al wires and packing factor of 2.5, this is a 3mm diameter bundle. Each SQP has 2x18=36 such twisted wire bundles at each end. Each side has 144 such bundles total. Material from all twisted pairs smeared over a shell of 15cm radius would be ~1.7% r.l. at perpendicular entry. Oct/07/2010Pixel PP0 opto replacement issues6

Questions / Tasks ETB Mechanical arrangement: board material / thermal contact / cooling loop ? Total power from LVDS repeaters ? LVDS repeater packaging footprint/constraints ? ETB layout to fit LVDS repeaters and wire soldering pads. Double sided ? Clarification of PP0 flex impedance Grounding scheme between PP0 and Optobox. Optobox end connection of large number of twisted pairs has same problem as IBL, to be resolved. Oct/07/2010Pixel PP0 opto replacement issues7