The "supercapacitor" assumes a new, flatter shape in Cooper Electronic Technologies' PowerStor F series. Intended to fit within PCMCIA cards and other low-profile designs, the supercapacitors come in an aluminum-foil polymer laminate package much like that used to build lithium-polymer batteries.
With the flat-pack design, designers can obtain supercapacitors as thin as 1 mm or less. The thinnest existing supercapacitors, the coin-cell types, may only be as thin as 1.5 mm. Coin-cell supercaps also suffer from relatively low capacitance and from impedance values that are at least 100 times greater than the PowerStor F series. Another alternative, cylindrical supercaps, are limited to diameters as low as 5 mm.
The PowerStor F series, or flat packs, can be constructed to a maximum thickness of 4 to 5 mm. Because of the flat packs' shape, designers can stack and connect individual capacitors in series. Cooper can fabricate the flat packs with footprints as large as 70 by 100 mm in the X- and Y-axis dimensions.
The flat packs can be manufactured in values ranging from 0.1 to 10 F using the company's ultra-low equivalent series resistance (ESR) "A" chemistry or its high-capacitance "B" chemistry. An example of a small, ultra-low ESR device would be a 17- by 40- by 1-mm supercapacitor with less than 0.1 ‡ of ESR. Users can achieve lower ESR and higher capacitance with larger volumes. In quantity, pricing is typically several dollars per unit.
Cooper Electronic Technologies, preliminary datasheet: www. cooperet.com/pdfs_html/PowerStorF_Specs.pdf; (888) 414-2645.
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