Reliability Effects with Proofing of Tantalum Capacitors

In traditional tantalum capacitors, the construction consists of a tantalum anode, Ta2O5 dielectric, and MnO2 as the cathode. The benefit of having MnO2, as the cathode, is the self-healing effect it provides. The conversion of MnO2 to a higher resistive state allows fault sites within the dielectric to be shut off from the rest of the capacitor. To mitigate problems developed during reflow, it is recommended for tantalum capacitors to be derated 50% for power-on reliability. Many times, customers are forced to use tantalum capacitors outside the recommended ranges. To improve power-on reliability, we recommend proofing the capacitors. Proofing, or controlled power up, is the process of activating the self-healing effects of tantalum capacitors. Although it has been shown to improve power-on performance and in some instances eliminate problems, the measurable effects of proofing have not been reported. This paper will investigate the measurable effects of proofing.