Patent Application
20060178025
The invention relates generally to electrical connectors and, more particularly, to an electrical connector for transmitting signals in differential pairs.
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.
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, that includes a plurality of signal pins or 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 or pins. Typically, the receptacle is a right angle connector that interconnects the back plane with the daughter board so that signals can be routed between the two. 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 that connect to the daughter board.
At least some board-to-board connectors are differential connectors wherein each signal requires two lines that are referred to as a differential pair. For better performance, a ground contact is associated with each differential pair. The receptacle connector typically includes a number of modules having contact edges that are at right angles to each other. The modules may or may not include a ground shield. As the transmission frequencies of signals through these connectors increase, it becomes more desirable to maintain a desired impedance through the connector to minimize signal degradation. A ground shield is sometimes provided on the module to reduce interference or crosstalk. In addition, a ground shield may be added to the ground contacts on the header connector. Improving connector performance and increasing contact density to increase signal carrying capacity without increasing the size of the connectors is challenging.
Some older connectors, which are still in use today, operate at speeds of one gigabit per second or less. By contrast, many of today's high performance connectors are capable of operating at speeds of up to ten gigabits or more per second. As would be expected, the higher performance connector also comes with a higher cost.
A need remains for a low cost differential connector with improved electrical characteristics such as reduced crosstalk and increased throughput.
In one aspect, an electrical connector is provided that includes a housing and a plurality of contact modules in the housing. Each contact module includes a mating edge and a mounting edge. Each mating and mounting edge has a row of contacts including signal contacts and ground contacts arranged in one of a first and second pattern. Adjacent contact modules in the housing have a different one of the first and second patterns. The first and second patterns each include pairs of signal contacts and individual ground contacts arranged in an alternating sequence. Each mating edge contact is electrically connected to a corresponding mounting edge contact by signal conductors and ground conductors extending along a predetermined path within the contact module. Each ground conductor has a width transverse to the predetermined path that is substantially equal to a combined transverse width across a pair of signal conductors in an adjacent contact module. The ground conductor thereby shields the pair of signal conductors in the adjacent contact module when the contact modules are arranged in the housing.
Optionally, each contact module further includes transition regions that join each signal and ground contact to one of the conductors. The ground conductors may include a slot extending longitudinally between the transition regions. Alternatively, the ground conductors may include a plurality of slots extending longitudinally between the transition regions, wherein the plurality of slots define a plurality of reinforcing bars therebetween.
In another aspect, an electrical connector is provided that includes a housing and a plurality of contact modules in the housing. The contact modules carry differential signals. Each contact module includes a mating edge and a mounting edge. Each mating and mounting edge has a row of contacts including signal contacts arranged in differential pairs and individual ground contacts. The signal and ground contacts are arranged in one of a first and second pattern, and adjacent contact modules in the housing have a different one of the first and second patterns. The first and second patterns each include pairs of differential signal contacts and individual ground contacts arranged in an alternating sequence. Each mating edge contact is electrically connected to a corresponding mounting edge contact by signal conductors and ground conductors extending along a predetermined path within the contact module. The ground conductors in each contact module cooperate with ground conductors in adjacent contact modules to substantially isolate each differential signal conductor pair from other signal conductors to reduce crosstalk in the connector when the contact modules are arranged in the housing.
In yet another aspect, a lead frame for an electrical contact module is provided. The lead frame includes a first row of mating contacts defining a forward mating edge and a second row of mounting contacts defining a mounting edge. The row of mating contacts and mounting contacts each include signal contacts and ground contacts arranged in one of a first and second pattern. The first and second patterns each include pairs of signal contacts and individual ground contacts arranged in an alternating sequence. Each mating edge signal and ground contact is electrically connected to a corresponding mounting edge signal and ground contact by signal conductors and ground conductors extending along a predetermined path within the lead frame. Each ground conductor has a width transverse to the predetermined path that is substantially equal to a combined transverse width across a pair of signal conductors in an adjacent lead frame having contacts arranged in the other of the patterns. The ground conductor thereby shields the pair of signal conductors in the adjacent lead frame.
The connector 10 includes a dielectric housing 12 having a forward mating end 14 that includes a shroud 16 and a mating face 18. The mating face 18 includes a plurality of contact cavities 22 that are configured to receive mating contacts (not shown) from a mating connector (not shown). The shroud 16 includes an upper surface 26 and a lower surface 28 between opposed sides 32. The upper and lower surfaces 26 and 28, respectively, each includes a chamfered forward edge 34. The sides 32 each includes chamfered side edges 38. An alignment rib 42 is formed on the upper shroud surface 26 and lower shroud surface 28. The chamfered edges 34 and 38 and the alignment ribs 42 cooperate to bring the connector 10 into alignment with the mating connector during the mating process so that the contacts in the mating connector are received in the contact cavities 22 without damage.
The housing 12 also includes a rearwardly extending hood 48. A plurality of contact modules 50 are received in the housing 12 from a rearward end 54. The contact modules 50 define a connector mounting face 56. In an exemplary embodiment, the mounting face 56 is substantially perpendicular to the mating face 18 such that the connector 10 interconnects electrical components that are substantially at a right angle to one another. The contact modules 50 include two module types, 50A and 50B as will be described.
A row of mounting contacts 86 extend along the contact module mounting edge 74. In an exemplary embodiment, the mounting contacts 86 are eye-of-the-needle contacts and are configured to be mounted to a circuit board (not shown). In other embodiments, the mounting edge 74 may be joined to an electrical component using other known contact types. Electrical paths within the contact module 50 interconnect the mating and mounting contacts 82 and 86 respectively. In an exemplary embodiment, the mating edge 80 and the mounting edge 74 are substantially perpendicular to one another.
The mating contacts 82 and mounting contacts 86 include both signal and ground contacts arranged in one of a first and second pattern that each includes pairs of signal contacts and individual ground contacts arranged in an alternating sequence. For example, in the first pattern, mating contacts 82A are ground contacts and contacts 82B are signal contacts. Similarly, along the mounting edge 74, mounting contacts 86A are ground contacts and mounting contacts 86B are signal contacts. Conductors within the contact module 50 interconnect mating ground and signal contacts 82A and 82B, respectively, with corresponding ground and signal mounting contacts 86A and 86B, respectively. The pairs of adjacent signal contacts 82B and 86B, at the mating edge 80 and the mounting edge 74, respectively, form a differential signal pair carrying differential signals. In the second contact pattern, the contacts 82 and 86 are arranged such that the two uppermost mating contacts in
Lead frame 100 includes a first row of contacts 82 that are mating contacts and which define a forward mating edge 130 of the lead frame 100. A second row of contacts 86 are mounting contacts and define a mounting edge 132 of the lead frame 100. The mating contacts 82 and the mounting contacts 86 both include signal contacts 82B, 86B and ground contacts 82A, 86A arranged in a first pattern that includes pairs of signal contacts 82B, 86B and individual ground contacts 82A, 86A, arranged in an alternating sequence as previously described. The mating contacts 82 are electrically connected to corresponding mounting contacts 86 by conductors 102 that extend along predetermined paths between transition regions 108, 110 that join the conductors 102 to the contacts 82, 86. The conductors 102 are arranged in the lead frame 100 in the same pattern as the contacts 82 and 86 in the lead frame 100.
Lead frame 200 is similar to the lead frame 100 and includes a first row of contacts 82 that are mating contacts and which define a forward mating edge 230 of the lead frame 200. A second row of contacts 86 are mounting contacts and define a mounting edge 232 of the lead frame 200. The mating contacts 82 and the mounting contacts 86 both include signal contacts 82B, 86B and ground contacts 82A, 86A arranged in a second pattern. The pattern includes pairs of signal contacts 82B, 86B and individual ground contacts 82A, 86A, arranged in an alternating sequence as previously described. The mating contacts 82 are electrically connected to corresponding mounting contacts 86 by conductors 202 that extend along predetermined paths between transition regions 108, 110 that join the conductors 202 to the contacts 82, 86. The conductors 202 are arranged in the lead frame 200 in the same pattern as the contacts 82 and 86 in the lead frame 200.
In the embodiments of
The embodiments herein described provide an electrical connector 10 having an improved lead frame 100, 200 for carrying differential signals. The lead frame includes ground conductors 104, 204 that have a transverse width that is substantially equal to a combined width of a pair of signal conductors 106, 206 in an adjacent lead frame. The ground conductor shields the signal conductors to reduce crosstalk in the connector. The lead frame also allows the connector to operate at higher frequencies with increased throughput.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
