Tantalum Capacitors

What is a Tantalum Capacitor?

A sub-type of electrolytic capacitors, tantalum capacitors are a passive component of electronic circuits composed of tantalum metal covered by a very thin layer of oxide.This layer acts as the dielectric for the capacitor and is surrounded by a conductive cathode.

What are the benefits of a tantalum capacitor?

The use of a thin dielectric layer results in a superior capacitance value per volume than other dielectric types, which in turn allows for smaller capacitors better-suited to modern technology systems. With an effectively unlimited shelf life, tantalum capacitors offer you excellent stability over time and can maintain expected capacitance across a variety of temperatures and frequencies. This will help your systems to behave reliably and consistently, especially as they also offer a very low Equivalent Series Resistance, reducing system losses. Tantalum capacitors withstand the soldering process well and are relatively low-cost, making them ideal foruse in their surface mounts.

What applications is a tantalum capacitor suited to?

Thanks to their compact size, reliability and high values of capacitance, tantalum capacitors are used in a variety of circuits including those found in laptops, mobile phones and cars. A tantalum capacitor SMD (surface mounted device) is the most common form in these instances. They are also popular in military and medical applications thanks to their ability to hold their capacitance over time, as well as audio amplifier systems where stability is crucial.

What other characteristics should I be aware of?

More so than other electrolytic capacitors, tantalums are highly polarised and very sensitive to reverse polarisation. Under pressure this can lead to the capacitor failing, so it’s important to be careful with their orientation during assembly. Their failure mode can be dangerous as a voltage spike can cause the tantalum anode to touch the manganese dioxide cathode. The reaction caused can lead to fire, so it’s a good idea to use current limiters and thermal fuses to prevent thermal runaway.