Polymer-Cathode Tantalum Capacitors

September 17, 2014

Jennifer Shuttleworth

With the recent focus on the efficiency of vehicle electronics, automotive manufacturers are looking for tantalum capacitors with lower equivalent series resistance (ESR). Polymer-cathode tantalum capacitors were previously unable to meet this demand. KEMET has been working to develop a new type of packaging that prevents hot air and humidity from reaching the polymer cathode of the tantalum capacitors, which helps remove the failure mechanism for these devices at high temperature and humidity levels. In tests on prototypes produced by KEMET, the new devices successfully met the requirements for the automotive industry’s AEC-Q200 standard, according to the company. Better packaging is the key to developing automotive-grade low-ESR tantalum capacitors, and KEMET will be launching the AEC-Q200 product in the near future. Shown in the image is the structure of a typical tantalum capacitor. The anode is typically made from sintered tantalum powder with a dielectric layer of tantalum pentoxide; the powder particles are very small and offer a very large surface area for the anode in a small space. The resulting high volumetric efficiency means tantalum capacitors can compete with the smallest capacitors on the market, claims KEMET.