Preliminary Design Review IDPU Backplane Preliminary Design Review Peter Berg University of California - Berkeley

Overview Backplane Overview Requirements Specifications Design Mass and Power Schedule Issues

Requirements Fault Protection IN.BKP-1. The IDPU BKP shall allow route power independently to instrument electronics allowing for autonomous fault protection features to ensure the health and safety of the instruments (ref IN.DPU-11) Commands/Telemetry IN.BKP-2. The IDPU BKP shall transport instrument data between instrument cards and the DCB.(ref IN.DPU-15) IN.BKP-3. The IDPU BKP shall transport engineering telemetry sufficient to safely turn-on and operate all instruments (temperatures, currents, voltages, and bi-levels) as defined in Instrument-IDPU ICDs(ref IN.DPU-16) IN.BKP-4. The IDPU BKP shall transport operational commands and test programs for all instruments as detailed in the Instrument-IDPU ICDs (ref IN.DPU-17) IN.BKP-5. The IDPU BKP shall transport initialization parameters to the Instruments as detailed in the Instrument-IDPU ICDs(ref IN.DPU-18)

Requirements Power Timing Signals IN.BKP-6. The IDPU BKP shall distribute a 2^23 Hz Clock from the DCB to the DFB and FGM(ref IN.DPU-23) IN.BKP-7. The IDPU BKP shall distribute a 1 Pulse Per Second (1PPS) to the DFB and the FGM(ref IN.DPU-25) IN.BKP-8. The IDPU BKP shall distribute a once-per-spin reference pulse (SRP) to the SST and ESA(ref IN.DPU-27) IN.BKP-9. The IDPU BKP shall distribute a Spin Sector Clock with 2^14 phase pulses per spin to the ESA and SST (synchronized with the SRP) (ref IN.DPU-28) IN.BKP-10. The IDPU BKP shall provide ESA and SST synchronization by distributing spin count data from the DCB to these systems. (ref IN.DPU-34) Power IN.BKP-11. The IDPU BKP shall transport Instrument regulated, switched and current-limited voltages as detailed in the Instrument-IDPU ICDs(ref IN.DPU-44) IN.BKP-12. The IDPU BKP shall transport LV transient power to actuators as detailed in the Instrument-IDPU ICDs(ref IN.DPU-45) Mechanical IN.BKP-13. The IDPU BKP shall accommodate at least five 6U VME cards(ref IN.DPU-51a)

Electrical Specification Specifications Electrical Specification Captured in THM_IDPU_001 revision H Details Interface Requirements for Each Board SST : Solid State Telescope Analog-to-Digital Conversion BEB : Boom Electronics Board DFB : Digital Fields Board FGE-PCB: Fluxgate Electronics and Power Control Board DCB-ETC: Data Controller Board and Esa-ssT Circuit LVPS : Low Voltage Power Supply connector

Electro-Mechanical Specifications Connectors VME standard connectors 3x32 format M55302 (Class1) Mate/Demate Cycles >500 Dielectric isolation >1000V (need 200V) J1 Location only Allows use of commercial backplanes for testing Female connectors (standard) to all boards except LVPS Male connector to LVPS Board-to-board Separation Current Spacing is 0.585” Driven by Board Heights Dependent upon tallest parts (e.g. large caps) Dependent upon electrical shielding Preliminary height has been checked by board designers

Design Considerations Grounds 5 Digital 8 Analog 7 Power Digital and Analog Signal Separation Digital Signals A1-C8 Analog & Power A9-C32 Voltage Capabilities Worst Case Floating Voltages +/-100V Isolation >1000V Current Capabilities Worst Case Current Req – Actuators @ 2A Pin Capabilities @ 3A

Design PINOUT (THM_IDPU_001H)

Design PINOUT (THM_IDPU_001H)

Design PINOUT (THM_IDPU_001H)

Design PINOUT (THM_IDPU_001H)

Specifications Connector Specifications (Board Interface)

Specifications Connector Specifications (LVPS Interface)

Mass & Power Power Mass Unterminated Backplane No power dissipation Assuming 0.585” board-to-board pitch Allocation 250 grams

Schedule Development Plan Use Commercial Backplanes DIN41612 for boards Allow FLT Board Dimensions to Define Spacing as needed Allow Chassis Fab/Assy Details to Define BKP features Layout and MIL-55110 PWB Fabrication Jan 2004 Coupon Checks at GSFC for Flight Backplanes

Issues Issues Board Design, Selection of Components Impact BKP Any of 5 boards can change BKP dimensions Recent Addition of SST reduced BKP pin margin to 8% If Necessary, can reduce Ground pins Board Height Impacts IDPU ICD Footprint