fields icdr – rfs analog dennis seitz 1 solar probe plus fields instrument cdr rfs analog dennis...

FIELDS iCDR – RFS AnalogDennis Seitz 1

Solar Probe Plus FIELDSInstrument CDR

RFS AnalogDennis N. Seitz

UC Berkeley [email protected]

FIELDS iCDR – RFS AnalogDennis Seitz

Outline

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• Introduction• EM Assembly• Block Diagram• Requirements• Changes• Testing• Peer Review • Status


FIELDS RFS Analog Location

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RFS Analog section of DCB• Separate power and ground planes• Entirely enclosed, top and bottom sides

SMA inputs from Preamps


FIELDS RFS Analog EM

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RFS Function Diagram

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RFS Analog Section Requirements

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Input Impedance MeetsRequirements

50 Ohms RTI Noise <7nV/√Hz from 30kHz to 16MHz 4Vpp Bandwidth 30kHz to 16MHz Output Impedance 100 Ohms Thermal Range Survival: -30C to +70C

Operational: -25C to +60C Quiescent Power ±6 @ 44mA = 528mW Radiation 20 krad total dose inside DPU

Functional Requirements:• Five inputs (V1, V2, V3, V4, SCM)• Two independent ADC signal conditioning chains• Each ADC chain:

• Single ended measurement of any selected input• Difference measurement of any two V1-V4 selected inputs • Selectable high or low gain for V1-V4 inputs• Balanced differential drive to ±1V range 12 bit ADC All EEE parts are SQPL, 100krad or better

EEE parts conditionally approved pending SET analyses


RFS BB to EM Changes

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• Increased bandwidth margin to >50MHz by replacing CD series multiplexers with HC series

• Increased gain• Decreased noise• Added ESD/DDD protection diodes• Added SCM input circuit to match TDS and

DFB


RFS Analog EM Testing - Performance

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Bench testing All functionality confirmed Input noise: 6.5nV/√Hz Bandwidth: 16 MHz Power consumption confirmed ADC interface performance

confirmed


DCB/RFS EM Testing

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Complete EM DCB/RFS Assembly1. Stand-alone functional and characterization2. Integration with PA and AEB:


Preamp EM Testing – Integration

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Integrated with complete FIELDS1 I&T


DCB/RFS in I&T Setup

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RFS Status and Schedule

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Two EM units built and tested• RFS Analog-only• RFS + DCB

FM schematic revisions completed 5 peer review recommendations FM parts procurement in progress SET analysis and PSA in progress EM characterization over temperature

planned Flight design is on track


RFS Backup Slides

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BACKUP SLIDES


RFS Noise + Galaxy Added in Quadrature

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RFS Pre-CDR Peer Review

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No. Detailed Comment Action Status

1 Quantify the coupling across the space on the board, to the RFS from the digital circuits.

The RFS section is isolated on all layers by a 1/8” wide gap in power and ground planes. Will perform end to end tests of RFS performance. If any crosstalk is identified from digital section we will troubleshoot.

√ closed

2 Qualify the flight balun transformer In progress. In progress

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How and where in the circuit, are you measuring phase relationships? Suggested test method would be with a scope within the circuit, and later when the circuit is closed up in the box. Resolve what phase measurements need to be performed, and what is the specification that needs to be met.

There is no phase specification. Any end-to-end phase relationships will be characterized during thermal test and calibrated out.

√ closed

4 Evaluate expected degradation in bandwidth with radiation exposure and over temperature.

Rad data shows DC changes only, and those are minimal; plenty of AD8001 GBW marginWill run gain and phase response tests to >500MHz to check phase marginWill identify what qualifies as acceptable phase margin.

√ closed

5 Is there enough phase margin in the anti-aliasing filter?

Will perform analysis and simulation to confirm that positive feedback of filter does not result in inadequate phase margin.

√ closed

fields icdr – rfs analog dennis seitz 1 solar probe plus fields instrument cdr rfs analog dennis...

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