Transient Modeling and Loop Stability in Spaceborne eGaN HEMT Low-Dropout Regulators Under Total Ionizing Dose

By Diego de Azcuénaga

The architecture of power management systems for spaceborne platforms demands semiconductor devices capable of operating deterministically under continuous ionizing radiation fluxes. In traditional space-grade LDO linear regulators, silicon MOSFETs serve as the primary pass element. However, prolonged exposure to TID induces the generation of electron-hole pairs within the gate dielectric of these devices. Holes trapped at the oxide interface shift the threshold voltage (V_th) and irreversibly degrade transconductance (g_m), typically by magnitudes exceeding 20%. This parametric degradation introduces severe non-linearities into the analog feedback loop, forcing designers to incorporate over-dimensioned design margins or complex dynamic compensation networks to prevent control loop oscillation or voltage hunting over the mission lifespan.

Read More – CIE Components in Electronics