Strategies for Manufacturing Ultra Low ESR Ta Capacitors
Leading edge designs for portable electronic devices require capacitors which deliver volumetric efficiency, high reliability, low cost, reduced propensity for ignition, and low Equivalent Series Resistance (ESR). Tantalum capacitors employing a conductive polymer cathode are uniquely capable of providing all of these critical characteristics. Tantalum capacitors have a long track record for unsurpassed volumetric efficiency and reliability. The introduction of conductive polymer cathodes enabled dramatic reductions in ESR and greatly increased resistance to ignition. The lower ESR and enhanced cap retention at high frequency of the conductive polymer construction enabled circuit designers to reduce the number of capacitors required to achieve design solutions, resulting in reduced cost. Although Multiple Anode Tantalum (MAT) designs are capable of achieving the lowest ESR possible with valve metal capacitors (< 6 milliohms), single anode Ta/polymer capacitors with ESR less than 9 milliohms are now. Single anode capacitors with ESR levels less than 7 milliohms are within reach. The ability to achieve ultra low ESR levels with single anode designs provides the lowest cost, high performance solution to many design requirements. This paper describes the strategy used by manufacturers to provide solid state capacitors with ever decreasing ESR levels.
Improved SMT Performance of Tantalum Conductive Polymer Capacitors with Very Low ESR
KEMET Electronics Corp has implemented several process and material improvements in order to improve the surface mount (SMT) performance of low ESR conductive polymer tantalum capacitors. This includes large case size (up to 7343-43) capacitors with ESR as low as 5 mΩ. Six Sigma methodologies (DMAIC: define-measure-analyze-improve-control) were used to structure the improvement process. This paper describes the project goals (define phase), new measurement techniques that had to be developed (measure phase), the conceptual model to explain SMT failures (analyze phase), process and material improvements (improve phase), and new control measures put in place (control phase).
Key Considerations for an Economic and Legal Framework Facilitating Medical Travel
Medical travel has the capacity to counter increasing costs of health care by creating new markets and increased revenue for health services, potentially benefiting local populations, economies, and health-care systems. This paper is part of a broad, comprehensive project aimed at developing a global health access policy (GHAP). It presents key issues to consider in terms of ensuring economic viability, sustainability, and limiting risk to the many stakeholders involved in the rapidly expanding industry of medical travel. The noted economic and legal barriers to medical travel are based on a synthesis of themes found in an extensive review of the available literature. Economic considerations, when setting up a GHAP, include a dynamic approach to pricing that is fair to the local population. Legal considerations include the implementation of international quality standards and the protection of the rights of those traveling as well as those of local populations in recipient countries. By taking into account these opportunities, the GHAP will more adequately address existing gaps in the economic and legal regulation of medical travel.