Showing papers on "Tantalum capacitor published in 2008"

Metal capacitor and method of making the same

Abstract: A method of making a metal capacitor includes the following steps. A dielectric layer having a metal interconnection and a capacitor electrode is provided. Then, a treatment is performed to increase the dielectric constant of the dielectric layer surrounding the capacitor electrode. The treatment can be UV radiation, a plasma treatment or an ion implantation. Accordingly, the metal capacitor will have a higher capacitance and RC delay between the metal interconnection and the dielectric layer can be prevented.

Method for manufacturing electrolytic capacitor and electrolytic capacitor

Abstract: A method of manufacturing an electrolytic capacitor including the following steps as well as an electrolytic capacitor manufactured by the method are provided. The method includes: a dispersion impregnation step of impregnating, with a dispersion containing electrically conductive solid particles or powder and a solvent, a capacitor element having an anode foil with a dielectric coating film formed thereon and an opposite cathode foil that are wound with a separator interposed therebetween; a dry step of evaporating the solvent after the dispersion impregnation step to form an electrically conductive solid layer on a surface of the dielectric coating film; and an electrolytic solution impregnation step of impregnating a gap in the electrically conductive solid layer with an electrolytic solution. Accordingly, an electrolytic capacitor that can be manufactured more easily that is excellent in voltage proofing property and that has a lower ESR and a lower leakage current is provided.

Solid-state electrolytic capacitor

Abstract: A solid-state electrolytic capacitor including a stacked body of a solid-state electrolytic capacitor element unit and an electrode conversion board. The unit includes two kinds of solid-state electrolytic capacitor elements. Each of first kind of solid-state electrolytic capacitor elements uses an anode body having a total thickness of an aluminum foil of 350 μm and a residual core thickness, i.e., the total thickness minus the thickness of an etched layer, is 50 μm. A second kind of solid-state electrolytic capacitor element provided on the mounting surface side uses an anode body having a total thickness of an aluminum foil of 150 μm and a residual core thickness is 50 μm. The electrode conversion board includes external anode and external cathode terminals that are arranged in a checkered manner and also includes, on the side opposite to the board, anode electrode and cathode electrode plates.

Method and device for predicting electrolytic capacitor defects, converter and uninterruptible power supply equipped with such a device

Abstract: A method and device for predicting defects of a capacitor, the method including determining the ripple voltage (Udc), the temperature (TP), and the current (Ic) of the capacitor, determining the value of an equivalent series resistance (ESR) of the capacitor, and the capacitance value (C) of the capacitor using a digital filter, determining information representative of the state of aging of the capacitor according to the temperature of the capacitor, and displaying that information and information representative of the value of the capacitance (C) and/or information representative of a cause associated with the state of aging according to the capacitance value. The device may include a converter and an uninterruptible power supply.

Modeling Dielectric Absorption in Capacitors

Abstract: Version 2d, June 2008 It is well known that dielectric absorption plays a critical role in determining the accuracy of analog sampled-data systems that are based on charge storage, such as sampleand-holds and switched-capacitor ADCs. Less appreciated, but no less important, is the role it plays in determining the quality factor, or Q, of the capacitor. Dielectric absorption has both storage and loss components that act, and are significant, over the entire usable frequency range of the capacitor.

Active voltage balancing of DC-link electrolytic capacitors

Abstract: DC voltage links of three-phase power converters are frequently equipped with a series connection of two electrolytic capacitors because of high voltage level. For such a configuration, usually resistors have to be arranged in parallel to each capacitor in order to balance the partial voltages. These balancing resistors, however, have to be dimensioned regarding the worst-case scenario of capacitor's leakage currents; such leakage can lead to high permanent dissipative losses that also appear in case of low actual leakage currents. To avoid these losses to a very large extent, a novel low-cost and robust active unit for replacing the passive balancing resistors is introduced. The paper describes the operating principle of the circuit, analyses the fundamental relationships relevant for the balancing characteristic and gives guidelines concerning component selection. Furthermore, simulation results as well as measurements taken from a laboratory prototype are presented.

Tantalum Powder and Methods Of Manufacturing Same

Abstract: Tantalum powder capable of providing a small-sized tantalum electrolytic capacitor while maintaining capacity is described. Tantalum powder in the present invention can be characterized in that the CV value is from 200,000 to 800,000 μFV/g, when measured by the following measuring method. Pellets are produced by forming tantalum powder such that the density is 4.5 g/cm3, then the pellets are chemically converted in a phosphoric acid aqueous solution of concentration 0.1 vol. % at a voltage of 6V and a current of 90 mA/g, and the chemically converted pellets are used as measuring samples to measure the CV value in a sulfuric acid aqueous solution of concentration 30.5 vol. % at a temperature of 25° C. under a frequency of 120 Hz and a voltage of 1.5V.

Methods of Fabricating Three-Dimensional Capacitor Structures Having Planar Metal-Insulator-Metal and Vertical Capacitors Therein

Abstract: Methods of forming a three-dimensional capacitor network may include forming a first horizontal MIM capacitor on a semiconductor substrate and forming a first interlayer insulating layer on the first horizontal MIM capacitor. A first vertical capacitor electrode is then formed in the first interlayer insulating layer and a second horizontal MIM capacitor is formed on the first interlayer insulating layer. This second horizontal MIM capacitor may be formed by forming an upper capacitor electrode and a lower capacitor electrode. The upper capacitor electrode may be electrically connected by the first vertical capacitor electrode to an upper capacitor electrode of the underlying first MIM capacitor. The lower capacitor electrode, which may be formed in the first interlayer insulating layer, may extend opposite the upper electrodes of the first and second MIM capacitors.

Implications of advanced capacitor dielectrics for performance of metallized film capacitor windings

Abstract: A range of high dielectric capacitor films is under development with the objective of improving the energy density of pulsed discharge capacitors. A substantial change in capacitor film dielectric constant has implications for capacitor design and function. This paper develops formulas for equivalent series resistance (ESR) and equivalent series inductance (ESL) of a cylindrical capacitor winding as a function of material properties and winding design. A numerical approach is used to investigate the frequency-dependent ESR and ESL, after which formulas are developed for winding inductance based on a resistive current distribution in the winding. Analyses are carried out for a cylindrical metallized film winding in which the return conductor is brought either through the center of the core on which the film is wound or coaxially up the outside of the winding, so that both connections are made from the same end of the capacitor with minimal inductance. The implications of moving to high dielectric constant film are investigated on the basis of this analysis.

An automatic technique to obtain the equivalent circuit of aluminum electrolytic capacitors

Abstract: This paper presents an economic and automatic experimental technique that allows the determination of the equivalent circuit of aluminum electrolytic capacitors at their operating conditions. The equivalent circuit of an electrolytic capacitor comprises an equivalent series inductance (ESL), an equivalent series resistance (ESR) and a capacitance (C). Both C and ESR values change with frequency, temperature and aging. The knowledge of the capacitor ESR value is essential to achieve the best design proposal for switch mode power supplies (SMPS) and in the selection of the best capacitors used in the DC link of adjustable speed drives (ASD). On the other hand, the accurate knowledge of the capacitor capacitance is also very important in the rectifiers design and in the choice of the best capacitor for the DC link of ASD. Moreover, the knowledge of both parameters allows the evaluation of the capacitor state condition. To implement the proposed technique, two distinct circuits should be considered. The first one accounts for the estimation of the ESR and reactance of the capacitor, while the second one allows the estimation of the capacitor capacitance. To implement the first circuit, it is necessary to put the capacitor under test in series with a resistor and connect them to a sinusoidal voltage. The relationship between the gain and phase of the capacitor voltage and current waveforms, obtained from sinusoidal fitting, gives enough information to compute both ESR and reactance of the capacitor. The second circuit is a simple charge/discharge circuit. From the relationship between the capacitor current and voltage, during discharge, it is possible to compute its capacitance using the least mean square algorithm.

High-Q, tunable-gap MEMS variable capacitor actuated with an electrically floating plate

Abstract: We proposed and developed a new MEMS variable capacitor that resembles the tunable-gap capacitor at first glance, but provides much better Q-factor thanks to reducing series resistance by the elimination of mechanical spring in the RF signal pathway using a new actuation method of moving electrically floating plate. The fabricated variable capacitor showed almost 200 % increment of Q- factor from the conventional tunable-gap capacitor. In addition, a variable capacitor array connected in parallel with four capacitors for larger capacitance was fabricated and measured. We achieved a tuning ratio of 41 % and (Q -factor of 34.9 at 5 GHz for the single capacitor and the tuning ratio of 29 % and (Q -factor of 39.8 at 1 GHz for the capacitor array.

Wet tantalum capacitor with multiple anode connections

Abstract: A capacitor assembly comprising a casing, an anode pack housed within the casing and comprising two or more anode pellets of anode active material electrically connected to each other by a bridge, and a cathode comprised of cathode current collectors including major faces with cathode active material provided thereupon is described. The bridge, which spans between sidewalls of the anode pellets, helps maintain them in a parallel alignment. The bridge is also a convenient location to connect the feedthrough wire that exits the casing through a glass-to-metal seal. The cathode current collectors are disposed between adjacent anode pellets and are electrically connected to each other and to the casing. A feedthrough wire electrically connected to the anode pack extends outside the casing in electrical isolation there from. An electrolyte is provided to activate the anode and the cathode.

Core-shell structured dielectric particles for use in multilayer ceramic capacitors

Abstract: This invention provides a method to make core-shell structured dielectric particles which consist of a conductive core and at least one layer of insulating dielectric shell for the application of multilayer ceramic capacitors (MLCC). The use of said core-shell instead of conventionally solid dielectric particles as the capacitor's active layers simplifies the MLCC manufacturing processes and effectively improves the MLCC properties. In particular, the use of core-shell particles with a thin shell of high permittivity dielectric material improves the capacitance volumetric efficiency, and the use of core-shell particles with a thick shell of dielectric will improve capacitor device's energy storage capacity as the results of improved electrical and mechanical strength.

High-frequency nonpolarity solid tantalum electrolytic capacitor with lead wire and manufacturing method thereof

Abstract: The invention discloses a high frequency nonpolarity solid tantalum electrolytic capacitor provided with a lead wire, which relates to the technical field of solid electrolytic capacitor. The basic structure of the electrolytic capacitor of the invention comprises an insulation shell (2), tantalum cores (1), a lead wire (4), a package layer of epoxy resin (3); wherein, adhesive silver slurry is used for firmly bonding two pieces of super thin tantalum cores (1) in series; then tantalum wires (6) on the two tantalum cores are respectively spot-welded on the lead wire; the tantalum cores spot-welded on the lead wire are put in the shell (2), and liquid epoxy resin is used for filling the gap within the shell until the shell is completely filled. The nonpolarity solid tantalum electrolytic capacitor with the lead wire of the invention has the advantages of good high-frequency performance, light weight, small installation size, convenient and firm installation, saving installation space, reducing weight, thereby being capable of widely applied to various electronic circuits.

Solid capacitor and manufacturing method thereof

Abstract: A solid capacitor and the manufacturing method thereof are disclosed. The solid capacitor consists of a dielectric layer and two electrodes. A plurality of holes formed by an opening process is disposed on surface of the dielectric layer. The two electrodes connect with the dielectric layer by the holes. By means of a plurality of high temperature volatile matters, the plurality of holes is formed on surface of the dielectric layer during sintered process. The holes are connected with the outside so as to increase surface area of the dielectric layer and further the capacity is increased. And the solid capacitor stores charge by physical means. Moreover, the solid capacitor can be stacked repeatedly to become a multilayer capacitor.

High Voltage Tantalum Polymer Capacitors

Abstract: Solid tantalum (Ta) capacitors with intrinsically conductive polymers as the cathode material have been widely used in the electronics industry due to their low equivalent series resistance (ESR) and “non-burning/non-ignition” failure mode. Intrinsically conductive polymers, commonly known as conductive polymers, are electrically conductive at the molecular level. Unlike polymeric materials whose electrical conductivity is imported from the presence of foreign conductive particles (for example silver paints or adhesives), a single molecule (a polymer chain) of an intrinsically conductive polymer is conductive. Various types of conductive polymers including polypyrrole, polyaniline, and polyethyldioxythiophene (PEDT) can be applied to dielectric oxides to serve as the primary cathode material for solid electrolytic capacitors. Two methods of coating the dielectric oxide with conductive polymers are widely used in the industry, in-situ polymerization and electrochemical polymerization. In in-situ polymerization the monomer of an intrinsically conductive polymer is brought into contact with an oxidizer to drive the polymerization reaction. In electrochemical polymerization the reaction is driven by an externally supplied current. The major drawback of conductive polymer capacitors, regardless of the type or method of application, is their relatively low working voltages compared to their MnO2 counterparts. For example, the maximum voltage rating of existing surface mount polymer tantalum capacitors is 25 volts, while that of their MnO2 counterparts is 50 volts. When subjected to voltages exceeding 25 volts, the existing polymer capacitors have, to varying degrees, reliability issues. This limitation has restricted the use of these devices to relatively low voltage applications (<20 volts). New developments in material and process technologies have overcome these limitations leading to the introduction of a new line of high voltage tantalum polymer capacitors with excellent long term reliability.

Implications of Advanced Capacitor Dielectrics for Performance of Metallized Film Capacitor Windings

Abstract: A range of high dielectric capacitor films is under development with the objective of improving the energy density of pulsed discharge capacitors. A substantial change in capacitor film dielectric constant has implications for capacitor design and function. This paper develops formulas for equivalent series resistance (ESR) and equivalent series inductance (ESL) of a capacitor winding as a function of material properties and winding design. A numerical approach is used to investigate the frequency-dependent ESR and ESL, after which a formula is developed for the inductance based on a resistive/capacitive current distribution in the winding. The analysis is carried out for a metallized film winding in which the return conductor is brought through the center of the core on which the film is wound so that both connections are made from the same end of the capacitor with minimal inductance. The implication of moving to high dielectric constant film is investigated on the basis of this analysis with the result that for direct film replacement and fixed winding capacitance, the ESR will increase in proportion to the film dielectric constant and the inductance will decrease slightly.

Capacitor and Method for Producing the Same

Abstract: A low-profile capacitor that can be bent and that has excellent interlayer adhesion strength. The capacitor includes a dielectric layer, a first capacitor electrode formed on a first main surface of the dielectric layer, a second capacitor electrode formed on a second main surface of the dielectric layer, and a lead electrode formed on the first main surface of the dielectric layer and electrically connected to the second capacitor electrode. The dielectric layer has a thickness of 5 μm or less. The sum of the thicknesses of the first and second capacitor electrodes is 5 μm or more and at least twice the thickness of the dielectric layer. The first and second capacitor electrodes and the lead electrode are formed of a malleable metal. The dielectric layer and the first and second capacitor electrodes are formed by being simultaneously sintered.

Dielectric fluid for improved capacitor performance

Abstract: A dielectric fluid thai provides improved resistance to device failure m capacitors comprising combinations of certain anthraqiunosxe compounds and scavengers. Capacitors including the dielectric fluid can have a higher discharge inception voltage and can have increased failure threshold voltages in comparison to capacitors made without the combination. Therefore, these capacitors are snore resistant to failures.

Tunable mems capacitor

Abstract: A capacitive MEMS structure comprising first and second opposing capacitor electrode arrangements, wherein at least one of the electrode arrangements is movable, and a dielectric material located adjacent to the second electrode arrangement, wherein the second electrode arrangement is patterned such that it includes electrode areas and spaces adjacent to the electrode areas, and wherein the dielectric material extends at least partially in or over the spaces.

Solid electrolytic capacitor for embedding into a circuit board

Abstract: An electrolytic capacitor that is configured to be embedded into a circuit board is provided. The electrolytic capacitor contains a capacitor element, anode and cathode terminations, and a case that encapsulates the capacitor element and leaves at least a portion of the anode and cathode terminations exposed that extend outwardly from opposite ends of the case. Each of the terminations possesses an upper surface that faces toward the capacitor element and a lower surface that faces away from the capacitor element. In contrast to conventional surface-mounted electrolytic capacitors, the upper surfaces of these exposed anode and cathode termination portions are mounted to the circuit board. In this manner, the capacitor may essentially be mounted “upside down” so that some or all of its thickness becomes embedded within the board itself, thereby minimizing the height profile of the capacitor on the board.

Chip-type solid electrolytic capacitor and chip-type filter

Abstract: A solid electrolytic capacitor is formed by stacking flat solid electrolytic capacitor elements. Negative electrode sections of a part of the solid electrolytic capacitor elements and negative electrode sections of the remaining part of the solid electrolytic capacitor elements are led out so as to be faced to each other, and are connected to the first and second negative electrode lead frames which are independent to each other, respectively. Two of negative electrode sections are insulated from each other in the solid electrolytic capacitor.

Norbornylene-based polymer systems for dielectric applications

Abstract: A capacitor having at least one electrode pair being separated by a dielectric component, with the dielectric component being made of a polymer such as a norbornylene-containing polymer with a dielectric constant greater than 3 and a dissipation factor less than 0.1 where the capacitor has an operating temperature greater than 100° C. and less than 170° C.

Capacitor structure with variable capacitance, and use of said capacitor structure

Abstract: The invention relates to a capacitor structure (1) with a variable capacitance, having at least one capacitor (101) with at least one capacitor electrode (5a, 5e), at least one opposing capacitor electrode (10a) which is arranged at a variable capacitor electrode separation (102) from the capacitor electrode (5a, 5e), and at least one actuator (103) for varying the capacitor electrode separation (102), having at least one actuator electrode (10b) for electrical actuation of the actuator by means of which the capacitor electrode separation is varied. The capacitor structure is characterized in that the actuator electrode and one of the capacitor electrodes of the capacitor are arranged alongside one another on a common mount (8). The actuator electrode and the capacitor electrode which is arranged alongside the actuator electrode are advantageously electrically isolated from one another. The actuation circuit and the function circuit are therefore decoupled. The actuator is advantageously a piezoceramic bending transducer. The capacitor structure is used, for example, in a voltage controlled oscillator (VCO). The capacitor structure is used in particular for telecommunications and mobile radio technology. The capacitor structure provides a basic module for the concept of “software defined radio” (SDR).

Pulsed Power Capacitors

Abstract: The U.S. Army Research Laboratory has sponsored a capacitor development program for film-dielectric capacitors. The program has evaluated dielectric materials for high energy density capacitors from industrial and academic research programs. High-performance capacitors have been developed that meet the needs of today's military applications. The performance of recently developed capacitors will be discussed.

Metal-metal capacitor and method of making the same

Abstract: A method of making a metal-metal capacitor is disclosed, in which a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer are formed in the order over a substrate; an upper capacitor is defined by etching using a first mask, wherein the stop of the etching can be controlled; a lower capacitor is defined by etching using a second mask; and an anti-reflective third mask is formed to cover the surface, and the capacitor border and metal interconnect conductive wire are defined, so as to make a metal-metal capacitor with a stable structure in a wide process window.

Solid electrolytic capacitor having current breaking function

Abstract: A solid electrolytic capacitor that can be miniaturized while maintaining the function for breaking current when excessive short-circuit current flows to a capacitor element. The solid electrolytic capacitor includes an anode body, a dielectric layer formed on the anode body, a conductive polymer layer formed on the dielectric layer, and a cathode layer formed on the conductive polymer layer. The conductive polymer layer contains thermally expandable graphite.

Capacitor, resonator, filter device, communication device and electric circuit

Abstract: A capacitor is provided with a first electrode (2) to which a direct current voltage is applied; a dielectric layer (3), which is arranged on the first electrode (2) and is composed of an oxide dielectric material; and a second electrode (4), which is arranged on the dielectric layer, has a first portion (41) where at least a part in contact with the dielectric layer (3) is composed of a conductive oxide material having oxidizing property, and has a direct current voltage lower than that applied to the first electrode (2) applied.

Sintered Anode Pellet Etched with an Organic Acid for Use in an Electrolytic Capacitor

Abstract: An electrolytic capacitor anode etched with an organic acid prior to anodic oxidation of the anode to create the dielectric layer. Without intending to be limited by theory, it is believed that the organic acid can etch away at least a portion of any oxides on the anode. This provides a relatively uniform surface for the creation of the dielectric, which in turn leads to a dielectric layer having a substantially uniform thickness and homogeneous amorphous structure and thus improved leakage current and stability. The organic acid may also have other residual benefits, such as removing any metallic impurities from the surface of the anode.