The subject matter herein relates generally to electrical connectors, and more particularly, to back plane connectors.
With the ongoing trend toward smaller, faster, and higher performance electrical components such as processors used in computers, routers, switches, etc., it has become increasingly important for the electrical interfaces along the electrical paths to also operate at higher frequencies and at higher densities with increased throughput. For example, performance demands for video, voice and data drive input and output speeds of connectors within such systems to increasingly faster levels.
In a traditional approach for interconnecting circuit boards, one circuit board serves as a back plane and the other as a daughter board. The back plane typically has a connector, commonly referred to as a header, which includes a plurality of signal contacts which connect to conductive traces on the back plane. The daughter board connector, commonly referred to as a receptacle, also includes a plurality of contacts. Typically, the receptacle is a right angle connector that interconnects the back plane with the daughter board so that signals can be routed therebetween. The right angle connector typically includes a mating face that receives the plurality of signal pins from the header on the back plane, and contacts on a mounting face that connect to the daughter board.
At least some right angle connectors include a plurality of contact modules that are received in a housing. The contact modules typically include a lead frame encased in a dielectric body. The lead frame includes a plurality of conductors that interconnect electrical contacts held on a mating end of the contact module with corresponding contacts held on a mounting end of the contact module. However, known connectors have problems operating at the higher performance levels of current systems. For example, known backplane connectors have limits to high speed electrical performance in the areas such as crosstalk, noise persistence, footprint impedance, and skew.
A need remains for a connector that overcomes at least some of the existing connector limitations to meet more demanding performance requirements in a cost effective and reliable manner.
In one embodiment, a contact module assembly is provided that includes a dielectric body having a mating end with a plurality of mating contacts and a mounting end with a plurality of mounting contacts. A lead frame is at least partially encased by the dielectric body, wherein the lead frame has a plurality of conductors representing both signal conductors and ground conductors extending along a lead frame plane. The signal and ground conductors extend from respective ones of the mating contacts and the mounting contacts, wherein at least some of the ground conductors include a mating contact terminal proximate the respective mating contact and a mounting contact terminal proximate the respective mounting contact. The ground conductors extend only partially between the mating contact and the mounting contact associated with the respective ground conductor such that a gap exists between the mating contact terminal and the mounting contact terminal of the ground conductor. A commoning member electrically connects the mating contact terminal and the mounting contact terminal of at least one of the ground conductors, wherein the commoning member is oriented in a non-coplanar relation with the lead frame plane.
Optionally, the dielectric body may have a trench extending entirely therethrough at least partially along the gap between the mating contact terminal and the mounting contact terminal of at least one of the ground conductors. The dielectric body may have a side substantially parallel to the lead frame plane, wherein the commoning member extends along the side and includes at least one tab extending therefrom that engages the lead frame. Optionally, at least two adjacent conductors define ground conductors. The two adjacent ground conductors may cooperate to form a ground pad, wherein the commoning member is mechanically and electrically connected to the ground pad. Optionally, the signal conductors may have different lengths defined between the mating and mounting contacts, wherein the signal conductors define differential pairs, and wherein the longer signal conductors within a differential pair include at least one compensation region being wider than adjacent regions thereof, and at least a portion of the compensation region is exposed to air by a window in the dielectric body.
In another embodiment, an electrical connector is provided that includes a housing, and first and second contact module assemblies held by the housing. Each of the contact module assemblies include a dielectric body having a mating end with a plurality of mating contacts and a mounting end with a plurality of mounting contacts, and a lead frame at least partially encased by the dielectric body. The lead frame has a plurality of conductors representing both signal conductors and ground conductors extending along a lead frame plane, wherein the signal and ground conductors extending from respective ones of the mating contacts and the mounting contacts. At least some of the ground conductors include a mating contact terminal proximate the respective mating contact and a mounting contact terminal proximate the respective mounting contact, wherein the ground conductors extend only partially between the mating contact and the mounting contact associated with the respective ground conductor such that a gap exists between the mating contact terminal and the mounting contact terminal of the ground conductor. A commoning member electrically connects the mating contact terminal and the mounting contact terminal of at least one of the ground conductors, wherein the commoning member is oriented in a non-coplanar relation with the lead frame plane.
In a further embodiment, a contact module assembly is provided that includes a dielectric body having a mating end with a plurality of mating contacts and a mounting end with a plurality of mounting contacts, the dielectric body defining at least one window therein. A lead frame is at least partially encased by the dielectric body, wherein the lead frame has a plurality of conductors representing both ground conductors and signal conductors arranged as differential pairs. The signal conductors extend from respective ones of the mating contacts and the mounting contacts such that at least some of the signal conductors have different lengths defined between the mating and mounting contacts. The longer signal conductor within a differential pair includes at least one compensation region being wider than adjacent regions thereof, wherein at least a portion of the compensation region is exposed to air by a respective one of the windows in the dielectric body.
As illustrated in
As illustrated in
In an exemplary embodiment, each of the contact module assemblies 50 includes a commoning member 60 that extends along one side thereof. Optionally, the commoning member 60 may define a ground plane for the respective contact module assembly 50. In the illustrated embodiment, the commoning member 60 includes a plurality of contacts 62, such as eye-of-the-needle contacts, that electrically and mechanically connect to the contact module assembly 50. Optionally, the commoning member 60 may be used to provide shielding between adjacent contact module assemblies 50.
As illustrated in
As illustrated in
As further illustrated in
By providing the gap 124, and removing at least a portion of the ground conductors between the mating and mounting contact terminals 120, 122, the noise persistence of the contact module assembly 50 may be reduced as compared to contact module assemblies having ground conductors that extend entirely between the mating and mounting contacts 20, 56. The amount of noise persistence (and noise persistence reduction) may be controlled by selecting a length of the gap 124 and a length of each of the mating contact terminal 120 and the mounting contact terminal 122. For example, the lengths of the mating contact terminal 120 and the mounting contact terminal 122 cooperate to define the length of the gap 124 (e.g. the distance between the mating contact terminal 120 and the mounting contact terminal 122), wherein the length of the gap 124 may be lengthened by decreasing the length of at least one of the mating contact terminal 120 and the mounting contact terminal 122. In some alternative embodiments, at least some of the ground conductors extend entirely between the mating and mounting contacts 20, 56, and the ground conductors may include terminals proximate the mating contacts 20 and/or the mounting contacts 56.
Returning to
In an exemplary embodiment, and as illustrated in
Each of the conductors 116 defining signal conductors have a predetermined length 142 defined between the mating contact 20 and the mounting contact 56. The lengths 142 of each of the signal conductors are different, due at least in part to the right angle nature of the contact module assembly 50. For example, the radially inner conductors 116 are generally shorter than the radially outer conductors 116. While each signal conductor within a differential pair has approximately equal lengths, because of factors such as the size constraint of the contact module assembly 50 and the cost or complexity of manufacture, the radially inner signal conductor within each differential pair is generally slightly shorter than the radially outer signal conductor. Any difference in length may lead to skew problems, as the signals within the differential pair travel along different path lengths.
In an exemplary embodiment, at least some of the signal conductors include compensation regions 144. For example, the radially outer signal conductors within each differential pair each include compensation regions 144. The compensation regions 144 are defined as having increased widths along the conductors 116. With reference back to
The compensation regions 144 generally have a longitudinal axis extending substantially parallel to the length of the conductor 116 extending from the mating contact 20 to the mounting contact 56. In the illustrated embodiment, the compensation regions 144 are generally rectangular extensions extending radially outward from the radially outer signal conductor. In an exemplary embodiment, the compensations regions 144 extend at least partially into the gaps 124 created by the absence of at least part of the ground conductors. The number, size and shape of the compensation regions 144 may be selected to substantially reduce skew. For example, by increasing the size or number of compensation regions 144, the skew may be reduced as compared to smaller or less compensation regions 144. Additionally, the increased width in the compensation region 144 controls the impedance, as the impedance changes with the change in dielectric constant.
In an exemplary embodiment, the mounting contacts 56 of the signal conductors, shown in the figures as signal mounting contacts 150, are different than the mounting contacts 56 of the ground conductors, shown in the figures as ground mounting contacts 152. For example, the ground mounting contacts 152 are represented by eye-of-the-needle contacts and the signal mounting contacts 150 are represented by micro-compliant pins that have a reduced cross section as compared to eye-of-the-needle pins. However in alternative embodiments, different types of contacts may be used for either the signal or ground mounting contacts 150, 152 and the signal and ground mounting contacts 150, 152 may be the same types of contacts.
In the illustrated embodiment, the ground mounting contacts 152 are longer than the signal mounting contacts 150 and are mated to the circuit board prior to the signal mounting contacts 150 being mounted thereto. The ground mounting contacts 152 are designed to engage the circuit board prior to the signal mounting contacts 150 to provide alignment and/or keying for the signal mounting contacts 152. For example, an alignment tolerance of the signal mounting contacts 150 may be less than a tolerance of the ground mounting contacts 152 such that the ground mounting contacts 152 are guided into respective mounting holes to more accurately align the signal mounting contacts 150 with respective signal mounting holes. Additionally, because the ground mounting contacts 152 are longer, and mounted within respective holes prior to the signal mounting contacts 150, the mating force of the electrical connector 10 (shown in
The signal mounting contacts 150 are generally smaller (e.g. narrower or have a reduced cross section) than the ground mounting contacts 152. As such, and as illustrated in
The lead frame 200 includes the mating and mounting contacts 20, 56, and the conductors 116 that extend along predetermined paths between each mating contact 20 to a corresponding mounting contact 56.
The first and second pinouts are different from one another such that, when the contact module assemblies 50A (having the lead frame 100 with the first pinout) is placed within the housing 12 (shown in
As with the lead frame 100, the conductors 116 of the lead frame 200 that define the signal conductors extend entirely between the respective mating and mounting contacts 20, 56. However, the conductors 116 defining ground conductors extend only partially between the respective mating and mounting contacts 20, 56 to form the gaps 124. The trenches 126 in the body 102 may be provided along the gaps 124. The conductors 116 defining the ground conductors have mating contact terminals 120 proximate the mating contacts 20, and the conductors 116 defining the ground conductors have mounting contact terminals 122 proximate the mounting contacts 56. Adjacent ground conductors form the ground pads 136 that receive the commoning member 60 (shown in
During assembly, the commoning member 60 is mounted to the contact module assembly 50A. The contacts 62 of the commoning member 60 are electrically and mechanically connected to the ground pads 136 (shown in
In an exemplary embodiment, when the commoning member 60 is installed, the commoning member 60 covers each of the signal conductors of the lead frame 100. As such, the commoning member may effectively shield each of the signal conductors from an adjacent contact module assembly when the contact module assemblies are assembled within the housing 12 (shown in
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means—plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
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Number | Date | Country | |
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20090093158 A1 | Apr 2009 | US |