Browse Prior Art Database

# Card Circuit Density Expander

IP.com Disclosure Number: IPCOM000084095D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 44K

IBM

## Related People

Marquardt, EE: AUTHOR

## Abstract

The number of logic circuits that can be packaged on a plug-in card is a function of the number of input-output signal pins that can be provided in the card plug-in connector.

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Card Circuit Density Expander

The number of logic circuits that can be packaged on a plug-in card is a function of the number of input-output signal pins that can be provided in the card plug-in connector.

The number of input/output (I/O) connector pins in the card plug-in connector, at the card-to-board interface, is limited by the tolerance buildup that occurs when the connector exceeds a given size, such as exceeding six (6) inches in row length for pins spaced by 1/10 inch. Card connector pins placed beyond the tolerance may not mate with their corresponding board pins. The card edge contacts shown in the figure circumvent this limitation to circuit density on a card.

The edge contacts comprise springs on one card which mate with contact pads on the adjacent card. Each opposing pair of edge contacts provide two different circuit connections.

The edge contacts join two logic cards in the same plane along their adjacent edges. The card edge contacts serve the purpose of joining printed-circuit patterns on one card to those on another card, specifically for the purpose of creating the effect of a larger homogeneous card, whose size is greater than that permitted by the restrictive tolerances governing a single card-to-board connector.

Advantages of adding the card edge contacts and joining a pair of cards are that the edge-joined cards: a. Permit the I/O contacts to be within tolerance limits on each of multiple cards, while supporting a large large increase in...