Browse Prior Art Database

Cooling and Shielding Arrangement for Multilayer Card Assemblies With Cryptographic Functions

IP.com Disclosure Number: IPCOM000038656D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 81K

Publishing Venue

IBM

Related People

DeSilva, DK: AUTHOR

Abstract

This article describes a combination heatsink and shield for printed circuit (PC) card assemblies with cryptographic functions which improves the transfer of heat to the ambient of any shielded multilayer assembly. PC card designers receive frequent requests to incorporate cryptographic capabilities into their card functions. The problem lies in the fact that this type of card requires tamper-proof shielding and is generally cooled by air. The devices in this type of assembly usually operate at a higher than normal temperature which, in turn, affects their reliability. In the arrangement disclosed herein, a combination shield and heatsink design uses two heat transfer modes to expel heat from the assembly. Fig. 1 shows the assembly in perspective view. Fig.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 69% of the total text.

Page 1 of 2

Cooling and Shielding Arrangement for Multilayer Card Assemblies With Cryptographic Functions

This article describes a combination heatsink and shield for printed circuit (PC) card assemblies with cryptographic functions which improves the transfer of heat to the ambient of any shielded multilayer assembly. PC card designers receive frequent requests to incorporate cryptographic capabilities into their card functions.

The problem lies in the fact that this type of card requires tamper-proof shielding and is generally cooled by air. The devices in this type of assembly usually operate at a higher than normal temperature which, in turn, affects their reliability. In the arrangement disclosed herein, a combination shield and heatsink design uses two heat transfer modes to expel heat from the assembly. Fig. 1 shows the assembly in perspective view. Fig. 2 is a cross-sectional view of the assembly showing how the shields go together on the card. Heat is conducted from the module cap to the upper shield-heatsink via copper leaf spring heatsinks and convected into the ambient air. Heat is conducted from the module substrate via the module ground pin(s) to the multilayer board. From here, the heat is conducted to both ends of the multilayer board where the ground plane is connected to the ground pads on both sides of the board. These pads provide for the attachment of both upper and lower shield-heatsinks. Once in place, heat can be transferred to the shield-heatsink and...