Browse Prior Art Database

Embedded, Back-Mounted, Low-Inductance Socket

IP.com Disclosure Number: IPCOM000122162D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Pence, WE: AUTHOR

Abstract

Disclosed is a concept for a low-inductance, IC socket. Using this technique reduces the parasitic inductance of conventional sockets, while retaining the ability to upgrade or replace components in the field.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Embedded, Back-Mounted, Low-Inductance Socket

      Disclosed is a concept for a low-inductance, IC socket.
Using this technique reduces the parasitic inductance of conventional
sockets, while retaining the ability to upgrade or replace components
in the field.

      A low-profile, backside-mounted socket is shown schematically
in the figure.  This approach is unique for the following reasons:
1) the socket is mounted from the backside of the card, rather than
being placed between the component and the card itself; 2) the socket
is embedded in the card during assembly, resulting in a socket which
is an integral part of the card; and 3) the component sees an
electrical environment which is not degraded by the presence of the
socket.

      The structure of the embedded socket is as follows: an array of
conducting hollow cylinders is fabricated on a leadframe such that
the cylinders are slightly larger than the diameter of the pins of
the package for which the socket is designed.  The leadframe is a
rigid metal structure which is punched and formed into an array of
cylinders connected by a frame as shown.  The rigidity of the
leadframe assures that the proper alignment can be maintained when
the array of cylinders is mounted into the card in the matching set
of Plated-Through Holes (PTHs).  These holes in the card are not
modified in any way from the standard process, so that the card could
accommodate the pinned component or the backside socket
interchangeably.  To further strengthen the socket and ease handling
during assembly, it is partially embedded in a molded plastic
housing.  This protects the portion of the socket which is exposed
under the card and prevents the cylinders and leadframe from damaging
other components.  The molding is accomplished without covering the
portion of the leadframe which will be excised after the mounting
operation. Excising the unwanted leadframe results in an array of
so...