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Technique for Increasing the Allowable Number of Simultaneous Switching Drivers

IP.com Disclosure Number: IPCOM000037665D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Fitzgerald, FC: AUTHOR

Abstract

Delta I noise is the voltage disturbance between power supply voltages on the output of quiet drivers that share the simultaneously switching driver power source. Crosstalk noise is coupled to the output of the quiet drivers also from nearby signal lines driven by the simultaneously switching drivers.

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Technique for Increasing the Allowable Number of Simultaneous Switching Drivers

Delta I noise is the voltage disturbance between power supply voltages on the output of quiet drivers that share the simultaneously switching driver power source. Crosstalk noise is coupled to the output of the quiet drivers also from nearby signal lines driven by the simultaneously switching drivers.

These noise sources are not additive if the quiet driver does not share the power source and does not share the line proximity with the simultaneously switching drivers. While this is often the case in modules, the present technique insures its existence.

The noise sources are also not additive if all of the nearby lines are switched simultaneous, i.e., if all of the lines within the group, in close proximity, are switched in the same direction at the same time (no nearby quiet line). This occurs for a major source of Delta I noise, i.e., for clock distributions where fan- out is increased by parallel drivers and lines.

The data bus is still another example of a major source of delta I noise that is not additive to crosstalk. The data bus receiver inputs often are gated "on" only after the simultaneously switched lines are quiet.

The present technique permits a wiring arrangement that allows increasing the number of simultaneously switching drivers in those cases where the delta I noise and the crosstalk are not additive. A wiring arrangement to increase the number of simultaneously swit...