Automotive

source: AVX Czech Republic s.r.o.; ESA SPCD 2018 Symposium

EPCI e-symposium library article

Tantalum electrolytic capacitors are known for their high capacitance and volumetric efficiency, parametric stability over a long service lifetime, and long-term reliability under harsh operating conditions. Conductive polymer electrolyte is becoming a popular option. The Polymer Tantalum capacitor was originally marketed toward consumer electronic applications, however after years of effort and continuous improvement, significant technological breakthroughs now permit use in many high-rel. applications, including automotive, defense, and aerospace, where more traditional capacitors (MnO2 type) still dominate.

The potential failure mechanisms include oxidative degradation of the conductive polymer, degradation by water condensation inside the capacitor body, or mechanical damage of the organic cathode layers. During recent years another issue has been identified – that of transient currents or a phenomenon dubbed anomalous charging current (ACC). This anomaly was associated with an absence of water within the cathode resulting in high current during charging and slow current decrease after charging. The phenomenon is most pronounced after reflow mounting but can be a concern for storage under conditions of very low moisture, such as aerospace environments.

This article presents a comparison of Polymer Tantalum capacitors before and after the principal reduction of cathode moisture sensitivity and the efforts to resolve the issue.

published by EPCI under approval of ESA SPCD 2018 organizing committee.

(more…)

0

---

---