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Method of Attachment of Chip Capacitors Which Prohibits Reversal

IP.com Disclosure Number: IPCOM000060177D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Girvan, EJ: AUTHOR [+2]

Abstract

A method is described which prevents reversal of tantalum chip capacitors during mounting. Tantalum chip capacitors are available for use in surface solder applications. However, if mounted in reverse bias, they result in a short and have been demonstrated to cause a fire. Contributing to this problem is the fact that the reversal cannot be detected by electrical testing, nor does the failure occur immediately. One solution to the foregoing problem would be a three-lead device, such as a capacitor, that could not be mounted in reverse bias. Another solution is to construct a three-lead capacitor when mounting the chip capacitors on the card. This can be accomplished by taking advantage of the orientation pin 10 protruding from the "+" side of the capacitor 11, as shown in Fig. 1, to create an interference.

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Method of Attachment of Chip Capacitors Which Prohibits Reversal

A method is described which prevents reversal of tantalum chip capacitors during mounting. Tantalum chip capacitors are available for use in surface solder applications. However, if mounted in reverse bias, they result in a short and have been demonstrated to cause a fire. Contributing to this problem is the fact that the reversal cannot be detected by electrical testing, nor does the failure occur immediately. One solution to the foregoing problem would be a three-lead device, such as a capacitor, that could not be mounted in reverse bias. Another solution is to construct a three-lead capacitor when mounting the chip capacitors on the card. This can be accomplished by taking advantage of the orientation pin 10 protruding from the "+" side of the capacitor 11, as shown in Fig. 1, to create an interference. The chip capacitors 11 are mounted in pairs on three pads 12, as shown below. If the capacitors 11 are mounted in reverse, an interference would be created, as shown in Fig. 2. With proper configuration of the pads on the card, electrical connection could be avoided when the capacitors 11 are reversed.

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