Improved Derating Procedure for Military Electronic Components Reflecting Temperature-Dependent Characteristics of Active Devices

Purpose: This study examines whether the derating parameter framework of NAVSEA SD-18 adequately captures the temperature-dependent behavior of active electronic components in military weapon systems. Based on this, we propose a new derating process that takes into account the characteristics of active components. Methods: A total of 53 active components from an air-to-ground guided weapon system were classified according to D-FMEA. Using eight representative temperature points derived from MIL-STD-810H, the SD-18 fixed-ratio criteria were quantitatively compared against datasheet characteristic curves for each component group. Discrepancies were classified as Type A (non-conservative: SD-18 permits stress beyond datasheet limits) or Type B (over-conservative: SD-18 restricts design beyond practical necessity). Results: The SD-18 framework does not capture key temperature-dependent parameters for MOSFETs and optocouplers. Furthermore, Type A errors were identified in MOSFETs, TVS diodes, and LEDs, where SD-18 criteria become non-conservative at elevated temperatures. Type B errors were found across microcircuit groups (Digital, Linear, MCU, and DSP). Conclusion: Based on these findings, a dual-criteria derating framework is proposed in which the SD-18 baseline is supplemented by datasheet-based criteria at the criteria-setting stage. For Type A components, datasheet curves should be applied above the identified crossover temperatures. For Type B components, thermal design verification may justify re-evaluation of allowable stress levels using datasheet junction temperature limits.