Tantalum Capacitors Review

Electronics, Instrumentation & Electrical Database

Tantalum Capacitors Review

A tantalum capacitor is comprised of a permeable tantalum center section surrounded by tantalum pentoxide. A tantalum wire is inserted into the center section and then extends axially from the component. The tantalum pentoxide layer is coated with manganese dioxide, graphite, a silver conductive coating and (finally) solder. Since 1960, tantalum capacitors have improved due to advances and development of higher charge tantalum powders, directly contributing to the design of smaller tantalum capacitors.

There are numerous advantages to using tantalum capacitors over other types of capacitors. First, tantalum capacitors have a higher volumetric efficiency (CV/cc) when compared to other types of capacitors. For instance, a 10-microfarad tantalum capacitor can replace a 100-microfarad aluminum capacitor. Tantalum capacitors are easily mounted onto circuit boards, and give engineering designers the ability to place these components in closely-confined printed circuit board space, as well as utilizing tantalum capacitors' excellent power dissipation characteristics. Second, tantalum capacitors have superior frequency characteristics than many other types of capacitors, including aluminum electrolytics. A comparable CV tantalum capacitor has an ESR ten times better than an aluminum electrolytic capacitor. Third, tantalum capacitors are highly reliable - electrical performance qualities do not degrade over time. Tantalum capacitors do not lose capacitance unlike electrolytic capacitors - in fact, the shelf life for tantalums is regarded as unlimited. Fourth, tantalum capacitors don't wear out - in fact, if there is an imperfection in the dielectric layer of a tantalum, the resistance of the manganese dioxide layer will typically convert to a form that is even more resistive. The new oxide form plugs up the faulty region and results in a reduction in current flow. Finally, tantalum capacitors have an excellent wide operating range, from -55 degrees Centigrade to +125 degrees Centigrade, with a minimal amount of degradation in electrical properties throughout this range.

As noted above, the advances and development of higher charge tantalum powders, have directly contributed to the design of smaller tantalum capacitors, resulting in the general downsizing of electronics. Tantalum capacitors can be found in laptop computers, airbag circuitry in cars and trucks, cell phones, pagers and a wide range of other electronic devices. The widespread use of tantalum capacitors in cell phones is one of the key factors in the significant reduction in the size of these devices during the past several years. Dell, Nokia, Hewlett-Packard, Motorola, IBM, Alcatel, Lucent, Compaq, Solectron and Ericsson are just a few of the companies that use tantalum capacitors in their wide range of electronic products.