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Electrostatic Discharge Protection for Card-Edge Connectors

IP.com Disclosure Number: IPCOM000038190D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hubing, TH: AUTHOR

Abstract

Circuit cards that have card-edge connectors are susceptible to damage from electrostatic discharge, which can occur when a connection is made. Charges flowing to or from the card can disable or weaken semiconductor components attached to the pins. One method for protecting these components is illustrated in the accompanying figure. The card-edge connector trace is divided into two parts. The part that first makes contact as the card is plugged in is connected to the semiconductor pin through a surface-mounted resistor (1 to 10 Megohms). The other part of the trace connects to the semiconductor pin directly, bypassing the resistor.

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Electrostatic Discharge Protection for Card-Edge Connectors

Circuit cards that have card-edge connectors are susceptible to damage from electrostatic discharge, which can occur when a connection is made. Charges flowing to or from the card can disable or weaken semiconductor components attached to the pins. One method for protecting these components is illustrated in the accompanying figure. The card-edge connector trace is divided into two parts. The part that first makes contact as the card is plugged in is connected to the semiconductor pin through a surface-mounted resistor (1 to 10 Megohms). The other part of the trace connects to the semiconductor pin directly, bypassing the resistor.

During insertion, the rate of charge flowing to or from the card is limited by the resistance. By the time the second part of the connector traces makes contact, the potentials of the semiconductor pins and the connecting device have been equalized. This technique avoids potentially large current transients from occurring while a connection is being made without affecting the operation or reliability of the card after it has been inserted.

Disclosed anonymously.

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