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System To Effect An RF Connection From An Electronic Chip Heatsink.

IP.com Disclosure Number: IPCOM000014552D
Original Publication Date: 2000-Sep-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Abstract

The disclosed invention is a method for grounding a heatsink applied to an electronic component. The problem is that when a heatsink with a thermal pad for heat transfer is applied to an electronic chip which uses AC current, essentially a capacitor is formed (Fig 1). When this occurs, there is an electrical potential difference between the electrical device and the heatsink resulting in electromagnetic radiation into the heatsink and transmitted to the fins. These fins act as an antenna and transmit these waves which contribute to EMC failures when testing for UL certification. If the heatsink is grounded, the electrical potential that would be transmitted to the fins would be transmitted to the system board through a ground contact where the signal could be dispersed without harm.

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System To Effect An RF Connection From An Electronic Chip Heatsink.

The disclosed invention is a method for grounding a heatsink applied to an electronic component. The problem is that when a heatsink with a thermal pad for heat transfer is applied to an electronic chip which uses AC current, essentially a capacitor is formed (Fig 1). When this occurs, there is an electrical potential difference between the electrical device and the heatsink resulting in electromagnetic radiation into the heatsink and transmitted to the fins. These fins act as an antenna and transmit these waves which contribute to EMC failures when testing for UL certification. If the heatsink is grounded, the electrical potential that would be transmitted to the fins would be transmitted to the system board through a ground contact where the signal could be dispersed without harm.

ELECTROLYTE

DETAIL A

UNGROUNDED STATE

THERMAL TAPE

CHIP

The structure solves this problem by guaranteeing a good electrical contact between the heatsink (E) and the board (D) to which the cooled chip is mounted.

GROUNDED STATE

ELECTROLYTE

DETAIL A

B

The features that guarantee this contact are the fingers (A) that contact the heatsink (B), the geometry of the grounding pad (C) on said board (D), 'feet' (E) that contact the grounding pad (C) and the structure
(F) that maintains stability upon installation. The 'fingers' are any geometry or number of geometries connected to the main structure that, when is contacted wit...