SPP-Fields Antenna Electronics Board (AEB) Concept Status Report

1. SPP-Fields Antenna Electronics Board (AEB)Concept Status Report J.W.Bonnell, S. Harris, S. Heavner Space Sciences Laboratory UC Berkeley (as presented by W. Rachelson) jbonnell@ssl.berkeley.edu sharris@ssl.berkeley.edu selda@ssl.berkeley.edu

2. Summary • Full time engineering support now available (Heavner), with part-time Science (Bonnell) and Systems (Harris) support as well for the AEB effort, so design progress is being made. • Close collaboration with PA design effort (Seitz, Bonnell, Goetz) to keep relevant interfaces (power, signal, noise) consistent. • Specification of breadboard (BB) AEB complete (1 channel – FGND, BIAS, STUB, SUN_SHIELD, +/- 100-V fixed, +/- 15-V floater). • AEB BB Design in progress (through Dec 2012): • Parts selection (switching supply drivers, DACs, bias output section transistors) • Schematic and bill of materials (BB and parallel 3DPlus packaging effort)

3. Scope of AEB Design Effort • Antenna Electronics Board (AEB, see following block diagram slide) • FGND Driver: • 1 channel each for 4 forward whips. • 1 channel for aft whip or dipole (TBR). • Sensor bias current, Stub and Shield bias voltage drivers: • 4 channels of each for 4 forward whips. • 1 channel of TBD subset for aft whip or dipole. • Whip preamp bias range relay control: • 1 channel each for 4 forward whips. • TBD channel for aft whip or dipole. • Floating and HV output stage Power Supplies: • 2 floaters to support opposing pairs of forward whips. • 1 floater (TBR) to support aft whip or dipole. • 1 HV (+/- 100-V) supply to support FGND and bias driver output stages. • Serial Command and Data (HSK) I/F to ICU. • Preamp-to-AEB Harnessing (TBR). • AEB-to-DFB Harnessing in MEB (TBR).

4. AEB – Block Diagram Replace with simple serial interface to ICU. CAL deleted. Floaters (1/axis) and HV NOT part of estimate for proposed AEB (assumed part of LNPS). Possible Channel 5 to support 3rd axis/tail sensor.

5. AEB – Power Service Concept • AEB uses existing switching supply designs (THEMIS, RBSP). • There will be changes to magnetics to accommodate changes in driver frequencies and SYNC requirements. • AEB takes regulated, filtered supplies from LNPS and providing following supplies: • ± 100-V supply (bias output stages). • ± 12-V analog (AEB input stages). • ± 15-V floaters (LF-PA supplies).

6. AEB Requirements (Dec 2012) • Preamp signal characteristics • DC voltage level: ± 60Vdc w.r.t. AGND (THEMIS-EFI-BEB) • AC voltage level: ± 10V w.r.t. floating ground (± 13V capability; RBSP-EFW-PRE) • Floating Ground Driver • Input: LF Preamp signal • Input filter roll off: 500 Hz (TBR; RBSP-EFW-BEB) • Output voltage level: ± 60Vdc w.r.t. AGND • Floating supply rails: ± 15Vdc (RBSP-EFW-BEB, -PRE) • Bias, Stub, Shield Drivers • Reference Input: LF Preamp signal • Reference input filter roll off: 500 Hz (TBR; RBSP-EFW-BEB, match FGND) • Output voltage level: Vref ± 40Vdc (max, programmable) w.r.t. AGND • DAC resolution: 16-bit (TBR; RBSP-EFW-BEB, THEMIS-EFI-BEB) • Max voltage required: ±100V (THEMIS-EFI-BEB and IDPU-LVPS) • Noise voltages at Bias, Stub, and Shield outputs consistent with noise floor requirements and predicted coupling to antenna (TBD).

7. Challenges and Plan for AEB Design Effort • Adapting existing THEMIS (BEB, LVPS) and RBSP-EFW (PRE) designs for SPP environments, resources, and requirements (all Phase B): • Equallychallengingradiation environment than THEMIS or RBSP, but less mass resources available for shielding: • Compile initial BOM, review against TID and SEE, and re-select parts as needed. • More functionality (bias control AND power supply) to pack into same or smaller PWB area, mass and power allocation than THEMIS, RBSP (and MEL values!): • Prepare initial layout using elements of existing designs to prove fit to PWA area. • Determine realistic mass and power estimates from elements of existing designs to refine mass and power impact of design options (e.g. 3rd axis measurement). • Consider and evaluate alternate part types (e.g. SMD rather than through-hole 100-V transistors) to trade change in design against mass/power/thermal benefits. • Demonstrating DC-LF compatability with MF and HF noise floor requirements: • HF noise floor requirements are one or two orders of magnitude more strict than THEMIS or RBSP: • Build breadboard channel, including floater and HV supplies using existing flight spare parts/hardware to allow for noise generation/succeptability testing and prove concept design will meet noise floor requirements at antenna (Phase B/early Phase CD).

8. BACKUP SLIDES

9. AEB – Mass Estimates (June 2012) • Floating and HV supply mass impact significant – minimum two-axis system is almost twice the mass carried in the proposal MEL! • Mass estimate needs to be refined with reference to THEMIS 100-V system, rather than RBSP-EFW 225-V system based on design decisions from June 2012.

10. AEB – Power Estimates (June 2012) • BEB power consumption can be significant. • Power estimate needs to be refined with reference to THEMIS 100-V system, rather than RBSP-EFW 225-V system based on design decisions from June 2012.