Patent Application
20110097934
Electrical connectors provide signal connections between electronic devices using signal contacts. Often, the signal contacts are so closely spaced that undesirable interference, or “cross talk,” occurs between adjacent signal contacts. Cross talk occurs when a signal in one signal contact induces electrical interference in an adjacent signal contact due to interfering electrical fields, thereby compromising signal integrity. Cross talk may also occur between differential signal pairs. Cross talk increases with reduced distance between the interfering signal contacts. Cross talk may be reduced by separating adjacent signal contacts or adjacent differential signal pairs with ground contacts.
With electronic device miniaturization and high speed signal transmission, high signal integrity electronic communications and the reduction of cross talk become a significant factor in connector design. It is desired to provide an improved connector reducing the problematic occurrence of cross talk, especially for high speed connectors.
One aspect of the present disclosure is related to a shorter electrical ground path at a mating end of the connector. In accordance with one embodiment, an electrical connector includes a housing and a plurality of electrical signal contacts carried by the housing. The electrical signal contacts each define mating ends and opposed respective mounting ends. The electrical connector further includes a ground plate having a body and at least a first mating end and a second mating end that each extend out from the body at a location such that the mating end of at least one of the plurality of electrical signal contacts is disposed between the first and second mating ends of the ground plate. The ground plate further includes a ground coupling beam connected between the first and second mating ends of the ground plate and isolated from the mating end of the at least one of the plurality of electrical signal contacts.
The foregoing summary, as well as the following detailed description of a preferred embodiment, are better understood when read in conjunction with the appended diagrammatic drawings. For the purpose of illustrating the present disclosure, reference to the drawings is made. The scope of the disclosure is not limited, however, to the specific instrumentalities disclosed in the drawings. In the drawings:
Referring initially to
The first electrical connector 22 includes a dielectric housing 31 that carries a plurality of electrical contacts 33, which can include signal contacts and ground contacts. The electrical contacts 33 may be insert molded prior to attachment to the housing 31 or stitched into the housing 31. The electrical contacts 33 define respective mating ends 38 that extend along the mating interface 30, and mounting ends 40 that extend along the mounting interface 32. Each of the electrical contacts 33 can define respective first and second opposed broadsides 39 and first and second edges 41 connected between the broadsides. The edges 41 define a length less than that of the broadsides 39, such that the electrical contacts 33 define a rectangular cross section. The mounting ends 40 may be press-fit tails, surface mount tails, or fusible elements such as solder balls, which are configured to electrically connect to a complementary electrical component such as the substrate 26, which can be configured as a backplane, midplane, daughtercard, or the like.
At least one or more pairs of adjacent electrical contacts 33 can be configured as differential signal pairs 45. In accordance with one embodiment, the differential signal pairs 45 are edge coupled, that is the edges 39 of each electrical contact 33 of a given differential pair 45 face each other along a common column CL. Thus, the electrical connector 22 can include a plurality of differential signal pairs arranged along a given column CL. As illustrated, the electrical connector 22 can include four differential signal pairs 45 positioned edge-to-edge along the column CL, though the electrical connector 22 can include any number of differential signal pairs along a given centerline as desired, such as two, three, four, five, six, or more differential signal pairs.
Because the mating ends 38 of the electrical contacts 33 are configured as plugs, the first electrical connector 22 can be referred to as a plug or header connector. Furthermore, because the mating interface 26 is oriented substantially parallel to the mounting interface 28, the first electrical connector 22 can be referred to as a vertical connector, though it should be appreciated that the first electrical connector can be provided in any desired configuration so as to electrically connect the substrate 28 to the second electrical connector 24. For instance, the first electrical connector 22 can be provided as a receptacle connector whose electrical contacts are configured to receive plugs of a complementary electrical connector that is to be mated. Additionally, the first electrical connector 22 can be configured as a right-angle connector, whereby the mating interface 30 is oriented substantially perpendicular to the mounting interface 32, and co-planar with the mounting interface 32.
Referring now to
The electrical signal contacts 44 define a respective receptacle mating ends 50 that extend along the mating interface 34, and opposed mounting ends 52 that extend along the mounting interface 36. Each mating end 50 extends horizontally forward along a longitudinal or first direction L, and each mounting end 52 extends vertically down along a transverse or second direction T that is substantially perpendicular to the longitudinal direction L. The leadframe assemblies 46 are arranged adjacent each other along a lateral or third direction A that is substantially perpendicular to both the transverse direction T and the longitudinal direction L.
Thus, as illustrated, the longitudinal direction L and the lateral direction A extend horizontally as illustrated, and the transverse direction T extends vertically, though it should be appreciated that these directions may change depending, for instance, on the orientation of the electrical connector 24 during use. Unless otherwise specified herein, the terms “lateral,” “longitudinal,” and “transverse” are used to describe the perpendicular directional components of various components. The terms “inboard” and “inner,” and “outboard” and “outer” with respect to a specified directional component are used herein with respect to a given apparatus to refer to directions along the directional component toward and away from the center apparatus, respectively.
The receptacle mounting ends 52 may be constructed similar to the mounting ends 40 of the electrical contacts 33, and thus may include press-fit tails, surface mount tails, or fusible elements such as solder balls, which are configured to electrically connect to a complementary electrical component such as the substrate 28, which can be configured as a backplane, midplane, daughtercard, or the like. The mating ends 50 are configured to electrically connect to the mating ends 38 of the complementary electrical contacts 33 when the electrical connectors 22 and 24 are mated. Each of the electrical signal contacts 44 can define respective first and second opposed broadsides 49 and first and second edges 51 connected between the broadsides 49. The edges 51 define a length less than that of the broadsides 49, such that the electrical signal contacts 44 define a rectangular cross section.
The mating end 50 of each signal contact 44 can include a neck 37 that extends out from the leadframe housing 48 along a longitudinally forward direction. The longitudinally forward direction can also be referred to an insertion or mating direction, as the connectors 22 and 24 can be mated when the electrical connector 24 is brought toward the electrical connector 22 when the electrical connector 24 is brought toward the electrical connector 22 in the longitudinally forward direction. The neck 37 can be laterally curved in a direction toward the outer surface 58 of the leadframe housing 48, so as to be generally aligned with corresponding mating ends 66 of a ground plate 62 (see
The mounting end 52 of each signal contact 44 can define a neck 53 that extends transversely down from the leadframe housing 48, and a mounting terminal 55 that extends down from the neck 53. The neck 53 and/or the mounting terminal 55 can be angled or curved toward the outer surface 58, and thus toward the ground plate 62. The mounting terminal 55 can define an eye-of-the-needle or any suitable alternative shape configured to electrically connect to the substrate 26. For instance, the mounting terminals 55 can be pressed into vias that extend into the substrate 26 so as to be placed in electrical communication with electrical traces that run along or through the substrate 26.
The electrical signal contacts 44 may define a lateral material thickness of about 0.1 mm to 0.5 mm and a transverse height of about 0.1 mm to 0.9 mm. The contact height may vary over the length of the right angle electrical signal contacts 44. The electrical contacts 44 can be spaced apart at any distance as desired, as described in U.S. patent application Ser. No. 12/396,086. The second electrical connector 24 also may include an IMLA organizer 54 that may be electrically insulated or electrically conductive. The electrical connector 24 can include an electrically conductive IMLA organizer 50 that retains the IMLAs or lead frame assemblies 46.
At least one or more pairs of adjacent electrical signal contacts 44 can be configured as differential signal pairs 45. In accordance with one embodiment, the differential signal pairs 45 are edge coupled, that is the edges 49 of each electrical contact 44 of a given differential pair 45 face each other along a common transverse column CL. Thus, the electrical connector 22 can include a plurality of differential signal pairs 45 arranged along a given column CL. As illustrated, the electrical connector 22 can include four differential signal pairs 45 positioned edge-to-edge along the column CL, though the electrical connector 24 can include any number of differential signal pairs along a given centerline as desired, such as two, three, four, five, six, or more differential signal pairs.
Because the mating ends 50 and the mounting ends 52 are substantially perpendicular to each other, the electrical signal contacts 44 can be referred to as right-angle electrical contacts. Similarly, because the mating interface 30 is substantially parallel to the mounting interface 32, the second electrical connector 24 can be provided as a vertical header connector. Moreover, because the mating ends 50 are configured to receive the mating ends 38 of the complementary electrical contacts 33 configured as plugs, the electrical signal contacts 44 can be referred to as receptacle contacts. It should be appreciated, however, that the second electrical connector 24 can be provided in any desired configuration so as to electrically connect the substrate 28 to the first electrical connector 22. For instance, the second electrical connector 24 can be configured as a header connector, and can be further be configured as a vertical connector as desired. When the connectors 22 and 24 are mounted to their respective substrates 26 and 28 and mated with each other, the substrates 26 and 28 are placed in electrical communication.
The first and second electrical connectors 22 and 24 may be shieldless high-speed electrical connectors, i.e., connectors that operate without metallic crosstalk plates between adjacent columns of electrical contacts, and can transmit electrical signals across differential pairs at data transfer rates at or above four Gigabits/sec, and typically anywhere at or between 6.25 through 12.5 Gigabits/sec or more (about 80 through 35 picosecond rise times) with acceptable worst-case, multi-active crosstalk on a victim pair of no more than six percent. Worst case, multi-active crosstalk may be determined by the sum of the absolute values of six or eight aggressor differential signal pairs that are closest to the victim differential signal pair, as described in U.S. Pat. No. 7,497,736. Each differential signal pair may have a differential impedance of approximately 85 to 100 Ohms, plus or minus 10 percent. The differential impedance may be matched, for instance, to the respective substrates 26 and 28 to which the electrical connectors 22 and 24 may be attached. The connectors 22 and 24 may have an insertion loss of approximately −1 dB or less up to about a five-Gigahertz operating frequency and of approximately −2 dB or less up to about a ten-Gigahertz operating frequency.
With continuing reference to
Referring also to
With continuing reference to
Each mounting end 52 of the ground plate 62 can define a neck 67 that extends transversely down from the body 64, and a mounting terminal 69 that extends down from the neck 67. The neck 67 and/or the mounting terminal 69 can be angled or curved toward the electrical contacts 44. The mounting terminals 69 can define an eye-of-the-needle or any suitable alternative shape configured to electrically connect to the substrate 26. For instance, the mounting terminals 69 can be pressed into vias that extend into the substrate 26 so as to be placed in electrical communication with electrical traces that run along or through the substrate 26.
Referring now also to
The ground plate 62 can be electrically conductive, and thus configured to reflect electromagnetic energy produced by the signal contacts 44 during use, though it should be appreciated that the ground plate 62 could alternatively be configured to absorb electromagnetic energy. For instance the ground plate 62 can be made from one or more ECCOSORB® absorber products, commercially available fro Emerson & Cuming, located in Randolph, Mass. The ground plate 62 can alternatively be made from one or more SRC PolyIron® absorber products, commercially available from SRC Cables, Inc, located in Santa Rosa, Ca. Furthermore, because the ground plates 62 are disposed between the signal contacts 44 of adjacent leadframe assemblies 46, the ground plates 62 can provide a shield between differential signal pairs 45 of adjacent columns CL that reduces cross-talk between the signal contacts 44 of adjacent leadframe assemblies 46.
The mating ends 66 of the ground plate 62 define ground mating ends, and are aligned along the transverse direction T, and are further aligned with the mating ends 58 of the signal contacts 44 along the transverse direction T. The mating ends 66 of the ground plate 62 can be longitudinally outwardly offset with respect to the mating ends 58 of the signal contacts 44. The mounting ends 68 are aligned along the longitudinal direction L, and are aligned with the mounting ends 52 along the longitudinal direction L. The mating ends 66 are positioned adjacent and/or between the pairs 45 of the mating ends 50 of the signal contacts, and the mounting ends 68 are positioned adjacent and/or between pairs of mounting ends 52. Thus, the mating interface 34 of the electrical connector 24 includes both the mating ends 50 of the electrical signal contacts 44 and the mating ends 66 of the ground plate 62, and the mounting interface 36 of the electrical connector 24 includes both the mounting ends 52 of the electrical signal contacts 44 and the mounting ends 66 of the ground plate 62.
In accordance with the illustrated embodiment, when the ground plate 62 is attached to the leadframe housing 48, the mating ends 66 are disposed between a pair of mating ends 50 of adjacent electrical signal contacts 44. The mating ends 66 can thus be are thus disposed in the gap 60 between the mating ends 50 of adjacent differential signal pairs 45, such that the mating ends 50 and 66 are equidistantly spaced along the mating interface 34 of the electrical connector 24. Likewise, the mounting ends 68 of the ground plate 62 are disposed in the gap 60 that extends between them mounting ends 52 of adjacent signal pairs 45, such that the mounting ends 68 and 52 are equidistantly spaced along the mounting interface 36 of the electrical connector 24.
The first plurality of leadframe assemblies 46a can be constructed identically, and configured such that when the ground plate 62 is attached to the leadframe housing 48, the mating interface 34 of at least one up to all of the leadframe assemblies 46a are arranged in a first pattern of mating ends 50 and 66. In accordance with the illustrated embodiment, the first contact arrangement is a repeating G-S-S pattern, whereby “G” identifies the mating end 66 the ground plate 62, and “S” identifies the mating end 50 of an electrical signal contact 44, and the two adjacent “S”s in the repeating G-S-S can identify a differential signal pair 45. Because the mating ends 66 and 50 are arranged in a repeating G-S-S pattern from the top of the mating interface 34 in a downward direction toward the mounting interface 36 along the respective column CL, the IMLA 26a and corresponding mating ends 50 and 66 can be said to define a repeating G-S-S pattern. The mounting ends 52 and 68 are therefore likewise arranged in the repeating G-S-S pattern from the rear end of the leadframe assembly 46a in a longitudinal direction toward the front end, or mating interface 34, of the leadframe assembly 46a
As illustrated in
Referring now to
The ground plate 64 can be retained by the leadframe housing 48 at a position such that the mating ends 63 of the ground plate 64 are be disposed between the mating ends 50 of adjacent differential signal pairs 45. The ground plates 62 can be inserted into the leadframe housing 48, overmolded by the leadframe housing 48, or otherwise carried or retained by the leadframe housing 48 such that the dimensions of the leadframe assembly 48 are substantially equal to those of conventional leadframe assemblies that contain discrete signal contacts and ground contacts overmolded by or otherwise coupled to a leadframe housing. The ground plate body 64 spans across a portion of a plurality up to all of the differential signal pairs 45 that is disposed in the leadframe housing 48. The leadframe assemblies 46 do not include discrete ground contacts, but rather includes the ground plate 62 that provides a low-impedance common path to intercept and dissipate stray electro-magnetic energy that otherwise would have been a source for cross talk between the electrical signal contacts 44 of adjacent leadframe assemblies 48. The ground plate 48 can be configured to reflect electromagnetic energy produced by the signal contacts 44 during use, though it should be appreciated that the plate could alternatively be configured to absorb electromagnetic energy. For instance, the ground plates 62 can be made of any lossy material, conductive or nonconductive.
Referring to
The mating ends 66 of the ground plates 62 can be sized such that the fingers 63a and 63b extend further longitudinally forward than the fingers 43 of the electrical signal contacts 44. Thus, the ground coupling beams 82 can be connected to the fingers 63a and 63b along a straight transverse direction, parallel to the column CL, between the fingers 63a and 63b of adjacent mating ends 66 at a longitudinal location that is spaced forward from the fingers 43 of the electrical signal contacts 44, such that the ground coupling beams 82 are electrically isolated from the electrical signal contacts 44. In accordance with the illustrated embodiment, the ground coupling beams 82 are connected to the distal tips 73 of the fingers 63a and 63b, such that the fingers 63a and 63b do not extend longitudinally beyond the ground coupling beams 82.
It should be appreciated, however, that the ground coupling beams 82 can be connected to any location of the mating ends 66 as desired. For instance, the ground coupling beams 82 can be connected to the mating ends 66 at locations that are aligned with the mating ends 50 of the electrical signal contacts 44, and can extend along a direction angularly offset with respect to the transverse direction (e.g., curved or bent) so as to avoid contact with the mating ends 50 of the electrical signal contacts 44. For instance, the distal tips 73 of the fingers 63a and 63b can be in-line with the distal ends of the fingers 43 of the electrical signal contacts 44. Each ground coupling beam 82 can define any cross sectional shape as desired, such as circular, rectangular, square, or any alternative shape.
Thus, the electrical connector 24 includes a plurality of electrical signal contacts 44 retained by the leadframe housing 48 and thus the dielectric housing 42. The electrical signal contacts 44 define mating ends 50 and opposed mounting ends 52. The electrical connector 24 further includes the ground plate 62 having the body 64, and at least a first mating end 66 and at least a second mating end 66 that extends out from the body 64 at a location such that the mating end 50 of at least one of the electrical signal contacts 44 is disposed between the first and second mating ends 66 of the ground plate 62. In accordance with the illustrated embodiment, the mating ends 66 of a pair of the electrical signal contacts 44, such as a differential signal pair 45, is received in a gap 79 disposed between the first and second mating ends 66 of the ground plate 62. The ground plate 62 further includes a third mating end 66 that extends out from the body 64 at a location such that the mating end of at least a second electrical signal contact 44, such as a pair of electrical signal contacts 44, or a differential signal pair 45, is received in a gap 79 disposed between the second and third mating ends 66. The ground plate 62 includes a first ground coupling beam 82 connected between the first and second mating ends 66, and a second ground coupling beam 82 connected between the second and third mating ends 66. Furthermore, because the first and second ground coupling beams 82 are connected between split fingers 63a and 63b of the second mating end 66 that are spaced from each other, the first and second ground coupling beams 82 are isolated from each other so that an electrical path established along the first and second ground coupling beams 82 does not travel directly from the first ground coupling beam 82 to the second ground coupling beam, but rather travels from the first ground coupling beam 82, along the second mating end, and into the second ground coupling beam 82.
Without being bound by theory, it is believed that connected mating ends 66 of the ground plate 62 allows fields of opposite polarity generated during use mix and cancel each other out, thereby “resetting” the ground. Accordingly, it is desired to shorten the length of unconnected ground paths. As described in U.S. patent application Ser. No. 12/393,794, it is appreciated that shortening the longest uncoupled electrical ground path length in the electrical connector assembly 20 when the two connectors 22 and 24 are mated can likewise shift the resonance frequency upwards so as to allow for a greater working bandwidth during operation. Because the ground paths are coupled at the substrate 28 to which the electrical connector 24 is mounted, and further at the ground plate body 64, the grounds reset at those locations. The mating ends 66 of the ground plate 62 and the mating ends 48 of the complementary electrical contacts 33 of the first electrical connector 22 also define an electrical ground path length. By positioning the ground coupling beam 82 at the mating ends 66 of the ground plate 62, the electrical ground path length at the mating interface 34 of the electrical connector 24 is shortened, thereby increasing the resonance frequency of the electrical connector 24 in the manner described above.
Accordingly, the electrical connector 24 is believed to provide an improvement over shieldless, high density, right-angle electrical connectors that have discrete ground contacts while at the same time avoiding a reduction in impedance matching without significantly increasing inductance. In accordance with one embodiment, a conventional electrical connector is modified by removing the discrete ground contacts and replacing the discrete ground contacts with the ground plate 62. Thus, the pre-modified electrical connector is substantially identical to the electrical connector 24 but for the removal of the discrete ground contacts and the addition of the ground plate 82. The ground plate 62 that has mating ends 66 and mounting ends 68 portions that align with the respective mating ends 50 and mounting ends 52 of the electrical signal contacts 44. In accordance with one aspect of the present disclosure, impedance is not significantly altered with respect to a pre-modified connector, inductance is lower than the ground contacts in the same pre-modified connector, crosstalk is lower as compared to the same pre-modified connector, and the overall dimensions of the pre-modified connector are substantially the same as those of the electrical connector 24.
As described above with reference to
The ground plate 62 of the second leadframe assemblies 46b is configured such that the mating ends 66 are disposed in the gap 60 when overmolded by or otherwise connected to the leadframe housing 48 of the second leadframe assembly 46b. Accordingly, each of the second plurality of leadframe assemblies 46b defines a contact arrangement in the repeating S-S-G pattern as described above.
It should thus be appreciated a plurality of ground plates 62 can be provided, such that at least a first ground plate 62 corresponding to a leadframe assembly of the first plurality of leadframe assemblies 46a is constructed differently than the at least a second ground plate 62 corresponding to a leadframe assembly of the second plurality of leadframe assemblies 64b. In particular, the mating ends 66 of the ground plates 62 of the second plurality of leadframe assemblies 46b extend from a location of the respective body 46 that is different than the location of the body 46 from which the mating ends 66 of the ground plates 62 of the first plurality of leadframe assemblies 46a extend. In accordance with the illustrated embodiment, the mating ends 66 of a first plurality of ground plates 62 (e.g., of the first plurality of leadframe assemblies 46a) are transversely offset with respect to the mating ends of a second one or a plurality of ground plates 62 (e.g., of the second plurality of leadframe assemblies 46b). Thus, a plurality of ground plates 62 can include a first ground plate and a second ground plate that is constructed differently than the first ground plate as described above.
The foregoing description is provided for the purpose of explanation and is not to be construed as limiting the invention. While various embodiments have been described with reference to preferred embodiments or preferred methods, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Furthermore, although the embodiments have been described herein with reference to particular structure, methods, and embodiments, the invention is not intended to be limited to the particulars disclosed herein. Additionally, it should be understood that the concepts described above with the above-described embodiments may be employed alone or in combination with any of the other embodiments described above. Those skilled in the relevant art, having the benefit of the teachings of this specification, may effect numerous modifications to the invention as described herein, and changes may be made without departing from the spirit and scope of the invention as defined by the appended claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/255,588, filed Oct. 28, 2009, the disclosure of which is hereby incorporated by reference as if set forth in its entirety herein.
| Number | Date | Country | |
|---|---|---|---|
| 61255588 | Oct 2009 | US |
