EIA 809-1999

$28.60

Solid Tantalum Capacitor Application Guideline

Published By	Publication Date	Number of Pages
ECIA	1999	28

Guaranteed Safe Checkout

Category: ECIA

If you have any questions, feel free to reach out to our online customer service team by clicking on the bottom right corner. We’re here to assist you 24/7.
Email:[email protected]

Description

Introduction

Solid electrolytic tantalum capacitors are those devices having
a sintered tantalum anode that incorporates a solid electrolyte
counter-electrode layer.

They are polar devices, having distinct positive and negative
terminals, and are offered in a variety of styles that include both
molded and conformal coated versions of radial, axial and surface
mount configurations.

These devices typically offer capacitance values from 0.1 µF to
1000 µF in voltage ratings from 2 V to 50 V (with a maximum
capacitance-to voltage combination of approximately 22 µF @ 50 V
for leaded styles or 22 µF @ 35 V for surface mount). Prime
characteristics include excellent temperature stability, volumetric
efficiency and compatibility with all automated assembly
systems.

The capacitor element, usually referred to as the "anode", is of
the same basic construction for all body styles.

Taking high-purity tantalum powder and pressing into an
appropriately shaped pellet makes the anode. The pellet is
generally cylindrical for axial and radial capacitors, and
rectangular in cross-section for surface-mounted capacitor. A pure
tantalum wire (the anode connection) is attached either by
insertion into the pellet before sintering, or welding after
sintering.

The sintering operation (where the anodes are heated up to
2000°C under a high vacuum or inert atmosphere) causes the
individual tantalum powder particles to interconnect and form a
single electrode of extremely high surface area in a very
small volume.

Tantalum is a valve metal whose amorphous oxide called tantalum
pentoxide (Ta₂O₅), can be formed to an
extremely uniform thickness over the entire anode surface by
electrolysis.

Although the tantalum pentoxide dielectric constant is high for
an electrolytic capacitor, it is much lower than achieved by
ceramic technologies. However, the relative thinness of the
dielectric (about 0.02 micrometers per volt) and the high surface
area (typically 250 cm² for a 22 µF/25 V rating)
results in highly volumetric-efficient devices.

Additional information