Aluminum electrolytic capacitors have evolved to meet the small-footprint needs of consumer and military applications thanks to new manufacturing techniques, including laser welds that extend their life even further
The ever-increasing trend toward miniaturization and flatness of electronic devices is a given for consumer markets, but now the demand for smaller power circuits has also spilled into industrial and military applications, in which space and weight savings are requirements for next-generation designs. The challenge for system design engineers is to source smaller components to save space without compromising system life and reliability.
This is especially difficult when sourcing for capacitors, which are often among the tallest components on a power-supply board. The alternative is to spread the capacitors over large areas of PC board when banked in parallel to meet minimum capacitance requirements for hold-up and bulk storage. However, capacitor manufacturing technology and techniques are improving, leading to the reinvention of the humble aluminum electrolytic capacitor to achieve flatter package styles to help power-supply designers meet their design needs.
As shown, the space savings potential of the THA series component is substantial when directly compared with boards populated with banks of axial and SMT aluminum electrolytic capacitors for the same capacitance and voltage ratings (5,800 µF, 35 Vdc at 85°C). Note that on the boards containing the tantalum and SMT devices, there is also a lot of unavoidable space between capacitors.
In addition to the compactness, tight seals, and robustness of the THA and MLSH components, use of a single component (versus multiple components) greatly simplifies assembly and significantly improves system reliability by reducing component count and connection points to the board. In the banked configurations, the failure of just one capacitor could prevent the entire bank from functioning.
As future applications demand thinner storage applications, we will continue to see a corresponding reduction in capacitor profiles. Cylindrical capacitors will continue to dominate where fully optimized space and weight requirements are not required. Even within the flat package design, there is room for continued improvement.
Cornell Dubilier - www.cde.com