Case 2157 ยท Public preview
Insufficient Voltage Derating Can Consume a Tantalum Capacitor's Surge Margin
A tantalum capacitor became a low-resistance failure and developed visible charring on its molded body.
Resistance testingOptical microscopyTargeted microsectioningSEMConstruction assessmentDerating review
What the evidence preview establishes
Electrical overstress produced breakdown near the outside of the tantalum slug, consistent with surge-current damage. The design operated the capacitor at 63% to 100% of rated voltage rather than the 50% derating cited in the report, leaving inadequate margin for reliable operation.
Why this case matters
Treat tantalum-capacitor derating as protection against surge sensitivity, not merely a nominal steady-state calculation. Correlate the physical breakdown site with actual operating voltage, transients, source impedance, and temperature before attributing a short to device manufacture.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.