1. Radiation Belt Storm Probes Electric Field and Waves Instrument
Digital Fields Board
Preliminary Design Review
Wesley D. Cole (Hardware Design Engineer)
Laboratory for Atmospheric and Space Physics
University of Colorado at Boulder
3-4 Sept. 2008
EFW INST+SOC PDR

2. EFW-DFB Organization
3-4 Sept. 2008
EFW INST+SOC PDR

3. EFW Block Diagram
You are
here
3-4 Sept. 2008
EFW INST+SOC PDR

4. Electric Fields Requirements
SOURCE
REQUIREMENT
EFW-45
Each EFW instrument shall perform interferometric timing measurements at high cadence using independent measurements from each of the paired probes, as follows:
-- for waves of 0.1 mV/m to 300 mV/m, velocity range of 0 to 500 km/s in spin plane, and wave spatial scales of 0.1 to 30 km when inter-probe wave coherence is greater than 0.5
-- cadence: 16,384 samples per second
-- sensitivity: mV/m
EFW-46
Each EFW instrument shall measure an electric field component perpendicular to the observatory spin axis (survey), as follows:
-- frequency range: DC to 15 Hz
-- magnitude range: 0 to 500 mV/m, at geocentric distances greater than 2.5 Re
-- cadence: 32 vectors per second
-- sensitivity: 0.3 mV/m or 10% for R > 3.5 Re, 3.0 mV/m for 2.5 Re < R < 3.5 Re
EFW-48
Each EFW instrument shall measure low frequency AC electric field cross-spectra, as follows:
-- frequency range: 10 Hz to 300 Hz
-- magnitude range: 80 dB
-- cadence: 6 seconds
-- sensitivity: 1 x V2/m2Hz at 30 Hz, 1 x V2/m2Hz at 300 Hz
EFW-49
Each EFW instrument shall measure an electric field component perpendicular to the observatory spin axis (burst), as follows:
-- frequency range: DC to 300 Hz
-- magnitude range: 0.3 to 500 mV/m
-- cadence: 512 samples per second
EFW-51
Each EFW instrument shall measure axial electric field components (survey), as follows:
-- magnitude range: 2 mV/m to 500 mV/m
-- sensitivity: 4 mV/m or 20% for R > 3.5 Re, 6 mV/m or 20% for 3.5 Re > R > 2.5 Re, 12 mV/m or 20% for R < 2.5 Re
EFW-52
Each EFW instrument shall measure axial electric field components (burst), as follows:
-- frequency range: DC to 256 Hz
-- magnitude range: 0.4 to 500 mV/m
-- sensitivity: 1 mV/m or 50 Hz
3-4 Sept. 2008
EFW INST+SOC PDR

5. EMFISIS SCM and MAG Requirements
SOURCE
REQUIREMENT
EFW-35
Each EFW instrument shall be capable of receiving 3D buffered analog search coil signals from the EMFISIS Waves instrument aboard its respective observatory, as follows:
-- frequency range: 10 Hz to 300 Hz
-- noise floor: < 1 x 10-8 nT2/Hz at 100 Hz
-- dynamic range: 90 dB
EFW-207
Each EFW instrument shall be capable of receiving DC-coupled, 3-axis data from the EMFISIS MAG instrument aboard its respective observatory, as follows:
-- through an analog interface
-- frequency range: from DC to 30 Hz
-- noise floor: < 2 nTRMS
-- dynamic range: 80 dB
EFW-43
Each EFW instrument shall measure 3-D low frequency AC magnetic field cross-spectra, as follows:
-- using the EMFISIS search coil signal
-- magnitude range: 90 dB
-- cadence: every 1 spin
-- sensitivity: 1 x Hz
EFW-44
Each EFW instrument shall measure burst AC magnetic field, as follows:
-- using EMFISIS search coil magnetometer data
-- frequency range: 10 Hz to 250 Hz
-- cadence: 512 samples per second
-- sensitivity: Hz
3-4 Sept. 2008
EFW INST+SOC PDR

6. General Instrument Requirements
SOURCE
REQUIREMENT
EFW-1
Each EFW instrument shall be designed for a total lifetime duration of 2 years plus 60 days.
EFW-7
EFW-8
Each EFW instrument shall be capable of operating in an orbit with perigee altitude 500 km to 675 km (TBR) and apogee altitude 30,050 km to 31,250 km (TBR).
Combined with the spacecraft charging model to determine the range of spacecraft potential: ± 225 V
ED&T 3.1.1
All parts used in RBSP observatory shall survive a total ionizing dose of 34 krad (Si) without parametric or functional failure.
ED&T
Parts susceptible to single event latch-up with linear energy transfer threshold less than 80 MeVsq cm/mg shall not be used in RBSP systems.
ED&T
SEUs in parts of non-critical systems shall not compromise flight system health or mission performance. Parts that may be susceptible to SEU shall be identified and submitted with the preliminary parts list to the APL RBSP Radiation Engineer for review.
ED&T
Hardware must operate through peak proton and electron flux.
ED&T 3.2
Deep Dielectric Discharge: Parts, assemblies and components shall either have to survive discharge, be grounded with low enough impedance to prevent charging, or shield with enough material to reduce the total accumulated charge below discharge level.
EFW-104
The EFW IDPU shall not exceed kg.
DFB allocation: kg, per RBSP-EFW-SYS_003D_Mass
EFW-63
Each EFW instrument shall not exceed the total power of W from the EFW Main 28 V Service.
DFB allocation: 1.8 W, per RBSP-EFW-SYS_004B_Power
3-4 Sept. 2008
EFW INST+SOC PDR

7. EFW – DFB Subsystem Performance Requirements
Product Type
Packet Name
Source Signals (Internal to DFB)
Measurement Range
Measurement Resolution
Driving Requirement
Survey Waveforms
E_SVY
E12DC, E34DC, E56DC
± 1 V/m
30 uV/m
EFW-45
V_SVY
V1DC, V2DC, V3DC, V4DC
± 225 V
6 mV
EFW-46
VAX_SVY
V5DC, V6DC
0.5 V/m 5%
EFW-51
Burst Waveforms
E_B1
EFW-49
EFW-52
V_B1
V1DC, V2DC, V3DC, V4DC, V5DC, V6DC
SCM_B1
SCM1, SCM2, SCM3
± 5 V
TBR
EFW-44
E_B2
E12DC, E34DC, E56DC,
E12AC, E34AC, E56AC,
Epar, Eprp, EparAC, EprpAC
AC: ± 200 mV/m
DC: ± 1 V/m
AC: 6 uV/m
DC: 30 uV/m
V_B2
V1AC, V2AC, V3AC,
V4AC, V5AC, V6AC
± 10 V
0.3 mV
SCM_B2
SCM1, SCM2, SCM3,
SCMpar, SCMprp
Wave Counter
SOL1
Select 1 of: E12AC, E34AC
0.25 to 0.5, 0.5 to 1,..., 128 to 256 16
3-4 Sept. 2008
EFW INST+SOC PDR

8. EFW – DFB Interface Documentation
DFB-IDPU Mechanical ICD (RBSP_IDP_MEC_200RevC)
Digital Fields Board Specification (RBSP_EFW_DFB_001A_SPEC Rev A)
AXB and SPB signals (Interface with BEB)
Interface with DCB
Interface with LVPS
Interface through backplane
EFW to EMFISIS Electrical Interface Control Document (RBSP_EFW_to_EMFISIS_ICD_revD.doc)
SCM and MAG signals from EMFISIS
3-4 Sept. 2008
EFW INST+SOC PDR

9. EFW – DFB Resources Resource Current Best Est. Allocation
Mass and Power Requirements
Mass CBE based on THEMIS heritage board
Power CBE based on analysis of current design and THEMIS heritage
LVPS will supply power to DFB through the backplane
± 10 V (Analog)
± 5 V (Analog)
+ 5 V (Digital)
+ 3.6 V (Digital)
+ 1.8 V (Digital)
Housekeeping Telemetry Requirements
DFB produces no analog housekeeping
FPGA diagnostic housekeeping sent to ground on request
Commanded through DCB
Resource
Current Best Est.
Allocation
% Growth Margin
Mass
0.438 kg (THEMIS)
0.548 kg
25%
Power, Avg
1.4 W
1.8 W
28%
Power, Peak
2.5 W
3-4 Sept. 2008
EFW INST+SOC PDR

10. DFB Block Diagram
3-4 Sept. 2008
EFW INST+SOC PDR

11. Radial and Axial Boom Signals
Input signal range: ± 225 V
Accuracy: 0.3 mV/m (for 100 m booms => 80 dB CMRR)
Vishay T decade divider (1/100), Ratio tolerance: 0.01%, Input impedance: 1 MW, 300 V, 100 mW/resistor
Same part used by THEMIS
3-4 Sept. 2008
EFW INST+SOC PDR

12. EMFISIS Signals and Differential Amp
Gain accuracy: 80 dB, Resistor tolerance: 0.01%
Vishay PHR or Z foil resistors
Deep dielectric discharge protection
3-4 Sept. 2008
EFW INST+SOC PDR

13. Active Filter Sallen-Key, 5-Pole, Low-Pass, Bessel, fc = 6.5 kHz
Passband gain = 1, Linear phase and constant group delay (to preserve waveform shape in passband)
Used 24 times in design
3-4 Sept. 2008
EFW INST+SOC PDR

14. Filter Test Results (Gain)
3-4 Sept. 2008
EFW INST+SOC PDR

15. Filter Test Results (Phase)
3-4 Sept. 2008
EFW INST+SOC PDR

16. NEW Filter Test Results (Square Wave)
3-4 Sept. 2008
EFW INST+SOC PDR

17. DFB Block Diagram
3-4 Sept. 2008
EFW INST+SOC PDR

18. Multiplexer Signal Lists
Channel 1 Signals Channel 2 Signals
V1DC V1AC
V2DC V2AC
V3DC V3AC
V4DC V4AC
V5DC V5AC
V6DC V6AC
E12DC FM1
E34DC FM2
E56DC FM3
E12AC SC1
E34AC SC2
E56AC SC3
Channel 1 signals meet the minimum science requirements
3-4 Sept. 2008
EFW INST+SOC PDR

19. DFB Block Diagram
3-4 Sept. 2008
EFW INST+SOC PDR

20. Analog to Digital Converter
Linear Technology LTC1604AIG
16-bit parallel output, Sample rate: 333 ksps (256 ksps required)
Successive approximation register with internal sample and hold
Internal clock
Internal reference (15 ppm/degree C)
S/N ratio: 87 dB minimum, THD: -100 dB typical
Integral linearity error: ± 2 LSB maximum
Operating temperature range: - 40 degrees C to + 85 degrees C
Manufactured on Mil-Spec line to Class S plastic specification
Radiation tested, no latchup protection required
Redundant cross-strapped design, either ADC can measure any signal
Flown on THEMIS
3-4 Sept. 2008
EFW INST+SOC PDR

21. DFB Block Diagram
3-4 Sept. 2008
EFW INST+SOC PDR

22. FPGA and SRAM Actel RTAX2000SL
Used for DSP functions, ADC and Mux control, SRAM interface and backplane interface
2,000,000 equivalent system gates
Total ionizing dose: 300 krad
1.5 V core voltage, 3.3 V I/O voltage
Honeywell HLX6228
Used for DSP scratchpad
Organized as 128K word x 8-bit Static RAM
32 ns read/write cycle times
Typical operating power: < 9 mW/MHz
Total ionizing dose: 1,000 krad
No latchup
3-4 Sept. 2008
EFW INST+SOC PDR

23. DFB Block Diagram
3-4 Sept. 2008
EFW INST+SOC PDR

24. Low Dropout Voltage Regulators
MS Kennedy MSK 5922 K RH (1.5 V and 3.3 V)
Total ionizing dose: 300 krad
Backplane supply voltages: 1.8 V and 3.6 V
Dropout voltage (from datasheet): 0.40 V IOUT = 2.5 A
Current manufacturer testing indicates a dropout voltage of only 0.15 IOUT = 0.5 A
MS Kennedy to add 0.5 A
Contingency plans
Raise backplane supply voltages to 1.9 V and 3.7 V
Use Berkeley LDO design (THEMIS heritage)
3-4 Sept. 2008
EFW INST+SOC PDR

25. DFB Thermal Test Requirements
REVISED
Requirements imposed at the EFW IDPU to SC interface:
+60°C Hot Survival Limit
+55°C Hot Operational Test Limit
-25°C Cold Operational Test Limit
-30°C Cold Survival Limit
3-4 Sept. 2008
EFW INST+SOC PDR

26. Parts Parts Engineer: Cat Brant
Parts procured or upscreened to EEE-INST-002 Level 2.
Parts derated per EEE-INST-002 with additional derating as required for radiation sensitivity.
Preliminary Identification List has been submitted to APL and has undergone review by Parts Control Board. Waiting for review by radiation group at APL.
LTC1604AIG has been approved for screening, qualification and radiation. LASP is to write waiver because part latchup rating is < 80 MeV. No additional testing required assuming we get the JWST parts.
LASP is participating in Actel FPGA common buy.
LASP requests radiation testing and upscreening of AD648 and OP262 by APL.
3-4 Sept. 2008
EFW INST+SOC PDR

27. EFW DFB Testing Frequency response of analog filters
Adjacent channel crosstalk
Multiplexer switching
ADC accuracy
Test of each flight configuration
Linear test of configurations not scheduled for flight use
FPGA DSP testing
Backplane interface test
End-to-end test
Thermal testing
Pre-delivery testing
3-4 Sept. 2008
EFW INST+SOC PDR

28. DFB GSE Block Diagram
3-4 Sept. 2008
EFW INST+SOC PDR

29. Current Status DFB ETU analog section being assembled and tested
FPGA testing to start in mid-September
Long lead time parts identified
One open item: MS Kennedy LDO voltage regulators
3-4 Sept. 2008
EFW INST+SOC PDR