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A polymer capacitor, or more accurately a polymer electrolytic capacitor is an electrolytic capacitor (e-cap) with a solid electrolyte of a conductive polymer. It is based on the use of an anode metal and the combination of a polymer electrolyte together with a liquid electrolyte. There are three different types: * Polymer tantalum electrolytic capacitor * Polymer aluminum electrolytic capacitor * Hybrid polymer capacitor Polymer niobium electrolytic capacitors are not yet in production. Polymer electrolytic capacitors in rectangular SMD chip style are available with a sintered tantalum anode or with stacked aluminum anode foils. In cylindrical SMDs (V-chips) style or as radial leaded versions (single-ended) they are available only with wound aluminum anode foils. Polymer capacitors are characterized by particularly low internal equivalent series resistances (ESR) and high ripple current ratings. Their electrical parameters have similar temperature dependence, reliability and service life compared to solid tantalum capacitors, but have a very much better temperature dependence and a considerably longer service life than aluminum electrolytic capacitors with non-solid electrolytes. In general polymer capacitors have a higher leakage current rating than the other solid or non-solid electrolytic capacitors. Polymer electrolytic capacitors are also available in a hybrid construction. The hybrid polymer aluminum electrolytic capacitors may have either a solid polymer electrolyte or a liquid electrolyte. These types are characterized by low ESR values but have low leakage currents and are insensitive to transient,〔 however they have a temperature-dependent service life similar to non-solid e-caps. Polymer electrolytic capacitors are mainly used as power supplies of integrated electronic circuits as buffer, bypass and decoupling capacitors, especially in devices with flat or compact design. Thus they compete with (MLCC), but offer higher capacitance values than MLCC capacitors. The also they display no microphonic effect. ==History== Aluminum electrolytic capacitors with liquid electrolytes were invented in 1896 by Charles Pollak, see electrolytic capacitor. Tantalum electrolytic capacitors with solid manganese dioxide electrolytes were invented by Bell Laboratories in the early 1950s, as a miniaturized and more reliable low-voltage support capacitor to complement the newly invented transistor,〔R. L. Taylor and H. E. Haring, "A metal semi-conductor capacitor," J. Electrochem. Soc., vol. 103, S. 611, November, 1956.〕〔D. A. McLean, F. S. Power, Proc. Inst. Radio Engrs. 44 (1956) 872〕 see Tantalum capacitor. The first tantalum capacitors (Ta-caps) with solid manganese dioxide electrolytes had 10 times better conductivity and a higher ripple current load than earlier types of non-solid electrolyte capacitors (e-caps). Additionally, unlike standard e-caps, the equivalent series resistance (ESR) of Ta-caps is stable in varying temperatures. During the 1970s, the increasing digitization of electronic circuits came with decreasing operating voltages, and increasing switching frequencies and ripple current loads. This had consequences for power supplies and their electrolytic capacitors. There was a need for capacitors with lower ESR and lower equivalent series inductance (ESL) for bypass and decoupling capacitors used in power supply lines,〔Capacitor Impedance Needs For Future Microprocessors, Larry E. Mosley, Intel Corporation, CARTS USA 2006 April 3–6, 2006 Orlando, FL, ()〕 seeRole of ESR, ESL and capacitance. A breakthrough came in 1973, with the discovery by A. Heeger and F. Wudl〔F. Wudl, "From organic metals to superconductors: managing conduction electrons in organic solids", In: Accounts of Chemical Research. 17, Nr. 6, 1984, S. 227–232, doi:10.1021/ar00102a005.〕 of an organic conductor, the charge-transfer salt TCNQ. TCNQ (7,7,8,8-tetracyanoquinodimethane or N-n-butyl isoquinolinium in combination with TTF (Tetrathiafulvalene)) is a chain molecule of almost perfect one-dimensional structure that has a 10-fold better conductivity along the chains than does manganese dioxide, and has a 100-fold better conductivity than non-solid electrolytes. The first aluminum electrolytic capacitors to use the charge transfer salt TTF-TCNQ as a solid organic electrolyte was the OS-CON series offered 1983 from Sanyo. These wound, cylindrical capacitors provided an improvement in conductivity (increased or decreased?) of the electrolyte by a factor of 10 as compared with the manganese dioxide electrolyte〔Shinichi Niwa, Yutaka Taketani, Development of new series of aluminium solid capacitors with organic Semiconductive electrolyte (OS-CON), Journal of Power Sources, Volume 60, Issue 2, June 1996, Pages 165–171, ()〕〔(Kuch, Investigation of charge transfer complexes:TCNQ-TTF )〕〔(Sanyo, OS-CON, Technical Book Ver. 15, 2007 )〕 Although Sanyo was the only manufacturer, these capacitors were used worldwide in many devices for applications which required the lowest possible ESR or highest possible ripple current. The technological advance was great, only one of these new OS-CON e-caps could replace three much more bulky "wet" e-caps or two Ta-caps. The success of these capacitors was great and by 1995, the Sanyo OS-CON became the preferred decoupling capacitor for the Pentium Processor used in IBM PC’s. The Sanyo OS-CON e-caps with TCNQ electrolyte was sold in 2010 to Panasonic after which Panasonic replaced the TCNQ salt in OS-CON capacitors with a conducting polymer but sold the capacitors under the same brand name. The next step in ESR reduction was the development of conducting polymers by Alan J. Heeger, Alan MacDiarmid and Hideki Shirakawa in 1975.〔About the Nobel Prize in Chemistry 2000, Advanced Information, October 10, 2000,()〕 The conductivity of conductive polymers such as polypyrrole (PPy) 〔Y. K. Zhang, J. Lin，Y. Chen, Polymer Aluminum Electrolytic Capacitors with Chemically-Polymerized Polypyrrole (PPy) as Cathode Materials Part I. Effect of Monomer Concentration and Oxidant on Electrical Properties of the Capacitors, (PDF )〕 or PEDOT 〔U. Merker, K. Wussow, W. Lövenich, H. C. Starck GmbH, New Conducting Polymer Dispersions for Solid Electrolyte Capacitors, (PDF )〕 is better than that of TCNQ by a factor of 100 to 500, and close to the conductivity of metals. In 1988 the first polymer electrolyte e-cap, "APYCAP" with PPy polymer electrolyte, was launched by the Japanese manufacturer Nitsuko with the intention of revolutionizing the industry 〔APYCAP Series, Function Polymer Capacitor, Nitsuko, Datasheet 1988〕 Nitsuko did not have great success with these capacitors, in part because they were not available in SMD versions. In 1991 Panasonic came on the market with its "SP-Cap", called polymer aluminum electrolytic capacitors. These aluminum electrolytic capacitors with polymer electrolytes reached very low ESR values that were directly comparable to ceramic multilayer capacitors (MLCCs). They were still less expensive than tantalum capacitors and with their flat design useful in compact devices such as laptops and cell phones they competed with tantalum chip capacitors as well. Tantalum electrolytic capacitors with PPy polymer electrolyte cathode followed three years later. In 1993 NEC introduced its SMD polymer tantalum electrolytic capacitors, called "NeoCap". In 1997 Sanyo followed with the "POSCAP" polymer tantalum chips. A new conductive polymer for tantalum polymer capacitors was presented by Kemet at the "1999 Carts" conference.〔(John Prymak, Kemet, Replacing MnO2 with Polymers, 1999 CARTS )〕 This capacitor used the newly developed organic conductive polymer PEDT (Poly(3,4-ethylenedioxythiophene)), also known as PEDOT (trade name Baytron®) 〔F. Jonas, H.C. Starck, Baytron, Basic chemical and physical properties, Präsentation 2003, ()〕 Two years later at the 2001 APEC Conference, Kemet introduced PEDOT polymer aluminum e-caps to the market.〔John Prymak, Kemet, "Performance Improvements with Polymer (Ta and Al)", 2001 APEC ()〕 The AO-Cap series included SMD capacitors with stacked anode in "D" size with heights from 1.0 to 4.0 mm, in competition to the Panasonic SP-Caps using polypyrrole at that time. A disadvantage of polymer electrolytic capacitors is their relatively high leakage current. Because the conductive polymer electrolyte provides no oxygen for self-healing processes the dielectric can be weakened, f. e. after soldering resulting in a high leakage current. For this reason around the turn of the millennium hybrid polymer capacitors were developed, which have in addition to the polymer electrolyte a liquid electrolyte connecting the polymer layers covering the dielectric layer and the cathode foil.〔NIC Components Corp., Hybrid Construction, Aluminum Electrolytic Capacitors ()〕 The non-solid electrolyte provide oxygen for self-healing purposes to reduce the leakage current. In 2001, NIC launched a hybrid polymer e-cap to replace a polymer type at lower price and with lower leakage current. As of 2015 the hybrid polymer capacitors are available from much more than only one manufacturer. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Polymer capacitor」の詳細全文を読む スポンサード リンク
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