Failure modes and reliability of DC to DC

Failure modes and reliability of DC to DC converters (New) Description: FY 08 Plans: DC to DC converters or voltage regulators are hybrid circuits utilized in numerous flight systems. With the goal of avoiding continued failures of converters in space hardware, a large inter center task has been established to develop recommendations for specifying parameters and test methods for DCDC converters. This task benefits from an inter NASA center collaboration (Goddard Space Flight Center (GSFC), Marshall Space Flight Center (MSFC), Johnson Space Center (JSC), and Jet Propulsion Lab (JPL); however, it does not include a reliability study of DC/DC converters. While some converter failures occur with no apparent cause after many cycles of operation, observations of aging related parametric shifts in maximum resistive loads and turn on voltages indicate a need to perform reliability investigations on these voltage regulators. Recent failures from commercial converters under tests at high temperature (125 C) indicate that input transistors and capacitors in some of these hybrids are weak links in the reliability of these voltage regulators. Some of the work in this task will pursue further understanding of their failure modes. Schedule/Costs: Par- 6 Total Full-Cost = • Evaluation of the reliability of failed components in flight DC to DC converters • Stress testing of available flight DC to DC converters to uncover failure modes and understand parametric shifts during aging • Monitor potential failure patterns after many cycles of operation in commercial voltage regulators. • This work will initially cover two manufacturers and up to four (4) regulator models. • Thermal chambers and testing electronics are operational and available for this work. • Testing will be done on voltage regulators leveraged from a larger task. Deliverables: • Results from reliability testing of DC to DC converters • Reliability investigation of problematic input transistors and capacitor elements (and perhaps other components if we observe other failures) • Failure mode investigation in different converter models (as many as time permits) NASA and Non-NASA Organizations/Procurements: Lead Center/PI: JPL/Rosa Leon Contributors: GSFC, JSC, MSFC, International Rectifier, and Crane Aerospace& Electronics Center Funding Split: JPL 100% • Transistors and capacitors that are found to be weak links in some of the DC/DC converter models (~ 5 $ K) • Some equipment rental fees from JPL instrument pool (cost TBD but minimal)