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FCU status

FCU status. HiFi consortium meeting 15 april 2003 Frans Zwart, Bert-Joost van Leeuwen. Contents. Design and production status Test status Main concerns Chopper control SMT. Design and production status [1]. FCU DM1 design completed

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FCU status

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  1. FCU status HiFi consortium meeting 15 april 2003 Frans Zwart, Bert-Joost van Leeuwen FCU status

  2. Contents • Design and production status • Test status • Main concerns • Chopper control • SMT FCU status

  3. Design and production status [1] • FCU DM1 design completed • FCU subsets delivered to SRON-G to support FPU testing: TU1 and TU2 • FCU TU3 ready for delivery, but now in use for full FCU tests (in conjunction with DM1). Delivery foreseen by the end of this month • FCU DM1 manufactured and 90% tested at board level • DM1 delivery mainly delayed due to late mechanism development (chopper, DRT to lesser extend) • DM1 delivery foreseen at 31-5-2003 FCU status

  4. Design and production status [2] • DM2 redesign now 60% complete • A specification for the FCU DM2/FM was reviewed at FCU pre-CDR, will be further updated and completed • Main design changes between DM1 and DM2: • Pulsed mixer deflux heater operation • EMC problem solutions: • Improved CMRR by additional filtering and enhanced ac balancing • RF filtering improved/added to prevent RF rectification at inputs • High speed opto-couplers replaced by low speed opto-couplers and analogue balanced interfaces • Power dissipation reduction • Deletion of mixer unit thermistors • Addition of frequency converter supply • Lay-out of IF board started now • Redesign of Mixer board 80% complete FCU status

  5. Design and production status [3] • Delivery of DM2 foreseen for December 2003 = compatible with recent FPU planning • No redesign for FM foreseen, other than lay-out changes for different DM and FM package types • Delivery of FM foreseen by 1-9-2004 • Recent acquisition of two analogue electronic design engineers provides good prospect for all design and test activities for DM2 and FM FCU status

  6. Test status FCU status

  7. Test status [1] • Main tests performed on DM1 model: • Thermal test on mixer and IF boards • EMC tests: • RS E-field 1MHz - 18GHz • CMRR 2Vp 50KHz - 50MHz • CS power lines dc, 100Hz - 10MHz • Safety related tests: • Static power failure tests (one out of 6 supplies fails) • Band and power supply switching transients on mixer and IF amplifier outputs • Full dc calibration of gain, offset and linearity • Transient response to verify settling time and to judge frequency stability and risk of oscillation • Noise of mixer bias voltage and IF amplifier drain voltage and current FCU status

  8. Test status [2] • Test results generally within specifications • Chopper transient ~3x too slow (20msec required, ~70msec achieved). FCU status

  9. Concerns - Chopper control - SMT FCU status

  10. Concerns - chopper [1] • Chopper transient response well outside required value. Required: 20msec, achieved now ~70msec • Non-linearity of actuator may cause specific operational constraints FCU status

  11. Concerns - chopper [2] • Recovery actions under investigation: • Optimisation of mechanism parameters: • Spring constant of pivots increased (stiffer) • Reduction of Eddy current damping (reduced metal volume of coil holder) • Extension of actuator magnets • Increased number of turns in actuator coil • Increased actuator transient current • no additional current available from dc/dc converter. Possible solution to use large capacitors (1000µF) • reduced resolution of D/A converter will introduce more position noise • enhanced current output stage required FCU status

  12. Concerns - SMT [1] • At SRON-U the assembly qualification process for various SMT parts is ongoing • Main qualification requirements are vibration and thermal cycling stresses • A dedicated printed circuit board was made to perform vibration and thermal cycling tests. Several mounting options were tested • Most critical package types are: • CQFP208 (ACTEL 54SX32RT) • CFP24 Radpack (SEI 7809 ADC) • Vibration tests have been performed: • Random 15gRMS for 10 minutes • Sine 5Hz - 2KHz sweep, 15 minutes at 15gRMS • Random 30gRMS 2 minutes FCU status

  13. Concerns - SMT [2] FCU status

  14. Concerns - SMT [3] • Vibration results: • Only the best supported CQFP208 survived the test • All CFP24 packages failed: leads broken, solder joints OK • CFP24 packages in best supported area’s sustained 15gRMS tests, failed in 30gRMS test only • Thermal cycling has been performed: • 200 cycles, -50 to +100°C • No further defects • Conclusions: • Vibration levels will be verified • CQFP208 mounting successful • CFP24 needs additional mechanical support FCU status

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