Electrical connectors – With coupling movement-actuating means or retaining means in... – For dual inline package
Reexamination Certificate
2001-01-09
2003-07-01
Ta, Tho D. (Department: 2833)
Electrical connectors
With coupling movement-actuating means or retaining means in...
For dual inline package
43, 43, 43, C235S441000
Reexamination Certificate
active
06585535
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS (IF APPLICABLE)
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT (IF APPLICABLE)
BACKGROUND OF THE INVENTION
The preferred embodiments of the present invention generally relate to electrical contacts and connectors for use with electronic packages or modules having leads arranged in a ball grid array (BGA) or a land grid array (LGA).
Electronic packages or modules with leads arranged in BGA or LGA configurations have been proposed in the past having relatively low vertical profiles to conserve space within an electronic assembly. Conventional packages and modules have been surface mounted directly to a circuit board in a soldering process wherein the leads are solder bonded to a corresponding array of circuit pads on the board. However, directly soldering electronic packages and modules to a circuit board has the drawback that the package is not easily removable for replacement or upgrade.
Connectors have been proposed in the past for removably mounting an electronic package or module on a circuit board. At least one conventional connector configuration comprises a flat dielectric housing which resides between the electronic package and the circuit board. The dielectric housing has an array of cavities in which are disposed electrical contacts arranged in correspondence with the array of leads of the electronic package. The contacts in the connection have ends projecting beyond the surfaces of the connector housing. When the electronic package or module is mounted on the connector, each contact has one end engaging the electronic package, while the other end engages a circuit pad on the circuit board. Compression forces are applied to the electronic package to assure firm engagement with the ends of the contacts. By way of example, the compression forces may be applied through pressure plates fastened together to sandwich the package, connector and circuit board therebetween.
Modem electronic components are designed with strict emphasis on their horizontal and vertical profiles. In certain applications, such as in laptop computers, cell phones, personal digital assistants, palm pilots and the like, a significant effort is made to minimize the vertical profile. Thus, it is desirable to maximize the working range within the height of a connector.
Conventional connectors for electronic packages are typically mounted to a printed circuit board via through holes. The sockets are located above plated round holes extending through the board, through which solder is inserted to mount the socket to the printed circuit board. In the more recent past, it has become desirable to surface mount connectors to printed circuit boards. Surface mounted sockets are not secured via through holes to the printed circuit board, but instead may be secured via bolts or other latching mechanisms to the board. As circuit designs become smaller, the vertical height of the connector becomes a greater concern. Conventional connectors have presented overall heights that are taller than desired for certain applications. The overall height of existing connectors is partially determined by the configuration of the contacts used therein.
In addition, existing connectors present a longitudinal and lateral envelope slightly larger than the size of the electronic package or module included within the connector. As circuit designs become smaller, it becomes more desirable that the longitudinal and lateral envelope of the connector not unduly exceed similar dimensions of the electronic module or package.
Conventional connectors include a socket and a cover mounted thereon to enclose the electronic module or package. Conventional covers are secured to the socket by a mechanism requiring a screwdriver to unscrew or pop the cover loose. Conventional latching mechanisms securing the cover to the socket add to the envelope of the connector, either in the vertical profile and/or in the longitudinal and/or lateral directions. It is desirable to minimize the increase in the connector envelope due to the cover latch.
Further, modem electrical equipment operates at very high switching frequencies, thereby giving rise to significant self inductance effects which may interfere with proper equipment operation. Self inductance may be reduced by reducing the length of a circuit path through a contact. However, it is also desirable to provide adequate length to a contact to permit deflection of the contact without deformation thereof and without degrading the biasing characteristics of the contact. In order to address the above-noted problems, contacts have been proposed with spring arms for deflection compliance and with shorting arms which interconnect free ends of the spring arms to provide a shortened current path through the contact. An example of one such contact is in U.S. Pat. No. 5,653,598. The contact configuration described in the '598 patent constitutes a compression mount, whereby the contacts are not soldered to the circuit board or to the electrical package. Thus, the contact configuration of the '598 patent forms a separable interface through the use of non-soldered interconnections. The contacts of the '598 patent utilize gold plating on the circuit board and on the electrical package to achieve adequate electrical connection characteristics therebetween.
However, in certain circumstances, it may be desirable to avoid or limit the use of gold plating on the circuit board and on the electronic package since gold may be overly expensive for certain applications. Therefore, an improved contact configuration is desirable which reduces the usage of gold to achieve satisfactory electrical connection characteristics, while enabling electronic packages to be easily removed without unsoldering such packages.
A need remains for all improved contact configuration that satisfies the above-discussed needs and that addresses other considerations that will be apparent from the following description and drawings.
BRIEF SUMMARY OF THE INVENTION
An electrical connector is provided in connection with at least one preferred embodiment of the present invention for electrically engaging an electronic module with a circuit board. The connector includes a socket having a base adapted to receive the module. The socket includes a plurality of board locking members mounting the socket to the circuit board. The socket also includes a plurality of contact cavities. Contacts are securely fixed in the contact cavities with each contact having a first engaging surface for electronically engaging the module and having a second engaging surface for electronically engaging the circuit board. A retention clip is removably secured to the socket and is configured to sandwich the module between the clip and socket with a predetermined amount of force. The socket may include end and side walls and a configuration of support ribs interconnecting the end and side walls. The socket and retention clip have a locking assembly interconnecting the retention clip and socket. The retention clip includes at least one biasing member abutting against and biasing the electronic module downward against the socket when the retention clip is secured to the socket. The biasing member provides sufficient force to bias the contacts until the first and second engaging surfaces are interconnected along a shortened circuit path.
According to at least one preferred embodiment, the biasing member includes a plurality of fingers mounted to the retention clip. The fingers project downward toward the socket with a predetermined amount of force. The fingers press against the module when the retention clip is secured to the socket. In an alternative embodiment, the biasing member includes fingers integrally formed with a top surface of the retention clip. The fingers bend downward into a cavity defined between the retention clip and socket, wherein the cavity receives the module. In accordance with an alternative embodiment, the biasing member includes fingers integrally formed with the side and end walls. The fing
McQuilkin Murr Keith
Mosser, III Ben Howard
Harvey James R.
Ta Tho D.
Tyco Electronics Corporation
LandOfFree
Electrical contact for LGA and BGA electrical packages does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrical contact for LGA and BGA electrical packages, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrical contact for LGA and BGA electrical packages will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3092657