Tantalum Capacitors

What is a tantalum capacitor?

A tantalum electrolytic capacitor is a type of electrolytic capacitor. It comprises a pellet of porous tantalum metal as an anode, covered by an insulating oxide layer that forms the dielectric, surrounded by liquid or solid electrolyte as a cathode. Because of its very thin and relatively high permittivity dielectric layer, the tantalum capacitor distinguishes itself from other conventional and electrolytic capacitors in having high capacitance per volume (high volumetric efficiency) and lower weight.

Tantalum capacitors are inherently polarized components. Reverse voltage can destroy the capacitor. Non-polar or bipolar tantalum capacitors are made by effectively connecting two polarized capacitors in series, with the anodes oriented in opposite directions.

What are the benefits of a tantalum capacitor?

Applications using tantalum capacitors take advantage of their low leakage current, high capacity and long term stability and reliability. For example, they are used in sample and hold circuits which rely on low leakage current to achieve long hold duration. They are also commonly used for power supply filtering on computer motherboards and cell phones due to their small size and long term stability, most often in surface mount form.

Tantalum capacitors are also available in military specifications versions (MIL-SPEC), which offer tighter tolerances and a wider operating temperature range. They are a popular replacement for aluminium electrolytics in military applications because they do not tend to dry out and change capacitance over time. Medical electronics also rely on tantalum because of their high stability. Audio amplifiers sometimes use tantalum capacitors where stability is a critical factor.