Gamma-ray Large Area Space Telescope GLAST Large Area Telescope GLAST Large Area Telescope LAT Level Requirement Sell-off Package for LVP159/LPS598 – DC Voltage Tolerance Requirement Owner: David Nelson Approval Date: Approved By: LAT Docs No: LAT-MD-08398
LVP159/LPS598 – DC Voltage Tolerance • Requirement: The LAT shall tolerate without damage or degradation DC voltages greater than 15.0 volts and less than 40.0 volts. • Verification Method: A5 • Verification Plan: • 1) This requirement has a waiver submitted to NASA. This analysis sets the minimum voltage to 18.5 volts. The CCR number is 433-0357. • 2) Analysis will show that all of the components are rated for 40 volt operation. • Test Script Run Info: • Worst Case Measured Data: N/A • Margin: N/A • Test/Analysis Summary: Analysis shows that the minimum voltage is 18.5 volts. All subsystem assemblies are rated to 40 volts.
LVP159/LPS598 – DC Voltage Tolerance • Analysis Report/Test Report Doc #(s): • CCR # 433-0357 is the analysis for 18.5 volt operation. • The 40 volt operation was successfully tested on each of the following subassemblies: • Tower Power Supply, LAT-DS-01482 • The test procedure for the Tower Power Supply is LAT-TD-01652 paragraph 5.5.2-6 • Crate Power Supply, LAT-DS-02390 • The test procedure for the Crate Power Supply is LAT-TD_01673 paragraph 5.4.1-35 • GASU Power Supply, LAT-DS-02413 • The test procedure for the GASU/ACD Power Supply is LAT-TD_01727 paragraph 5.4.1-36 • The PDU 40 volt compliance is by analysis. • The PDU Assembly schematic diagram is LAT-DS-01696. • The PDU CCA schematic is LAT-DS-02127. • LAT-DS-02127 sheet 6 of 66, PDU_3_3_V_PS is the schematic of the 28V to 3.3V power converter. • There is a series of capacitors, C42-C47 & C49 which is rated at 50V • An input filter, ARF461 which is rated at 80 volts. • http://www.irf.com/product-info/datasheets/hirel/arf461.pdf • A DC-DC converter, MAX-724, rated at maximum of 45 volts • http://pdfserv.maxim-ic.com/en/ds/MAX724-MAX726.pdf • Two power FETs are used to switch spacecraft power to loads are rated at 60V • http://www.irf.com/product-info/datasheets/data/irhna597064.pdf • http://www.irf.com/product-info/datasheets/data/irhnj597034.pdf • All wire used is MIL-W-22759 rated at 600V
LVP159/LPS598 – DC Voltage Tolerance • Compliance Statement: LAT Complies • NCRs/JIRAs: None