M39003/01-7096H

Tantalum Capacitors

M39003/01-7096H is a tantalum capacitor, which is a type of electrolytic capacitor consisting of a pellet of tantalum metal as an anode, covered by an insulating oxide layer that forms the dielectric, surrounded by liquid or solid electrolyte as the cathode. The main advantage of tantalum capacitors are small size, high capacitance, low leakage, and stability over time at the cost of lower voltage ratings and higher cost.

Application Field

Tantalum capacitors find wide use in applications from consumer electronics, computers, and automotive to defense and aerospace. Common applications for tantalum capacitors include filtering, energy storage, bypassing, and coupling and decoupling. Being highly reliable, rugged and compact, they are indispensable in small switching supplies, battery-powered devices, dc-to-dc converters, pulse circuits, and other applications.

Working Principle

Tantalum capacitors are formed by coating a solid tantalum anode with an insulating oxide layer to form the dielectric. This layer is often formed using DC anodization, during which a direct electric current is passed through the tantalum electrolyte and the oxide layer is formed on the anode surfaces. The thickness of the oxide layer determines the capacitance of the capacitor. The capacitor is then polarized through the application of a voltage, forcing the ions of the anode oxide to migrate and align with the anode surface.

The oxide layer forms an electric double layer and behaves like the dielectric of any other electrochemical capacitor. When the voltage across the terminals of the tantalum capacitor is decreased, the dielectric returns to its non-polarized state, allowing the capacitor to discharge. This principle is referred to as the “switch-on discharge phenomenon”.

The selection of the electrolytic material for the tantalum capacitor is an important factor to consider during design. Although the operating temperature of the capacitor will depend on the type of electrolyte material used, some materials also offer better corrosion protection or provide higher capacitance. In addition, the electrical properties of the tantalum capacitor can be enhanced by adjusting the physical geometry of the anode and the thickness of the dielectric.