Patent Application
20130316585
The subject matter herein relates generally to card edge connectors.
There are numerous protocols used to communicate information among digital devices. Various standards have been applied to permit connection of peripheral devices such as network interface cards, storage adaptors, graphics cards, and other devices to a computer motherboard. For example, card edge connectors, connected to the motherboard, receive circuit cards or peripheral expansion boards. The peripheral expansion boards are available in a variety of form factors. Some peripheral expansion boards feature small form factors applicable to space constrained applications, such as notebook computers. Some peripheral expansion board form factors are targeted at desktop computers where more space is available to accommodate a larger form factor. One protocol which has been developed for transporting computer bus protocols is the PCI-Express (PCIe) protocol. Other protocols exist.
The card edge connectors include a card edge slot that receives the peripheral expansion board. The card edge connector holds many contacts for interfacing with corresponding pads on the peripheral expansion board. Due to size constraints, and the desire for smaller and smaller connector footprints, the many contacts are arranged in close proximity within the connector and at the mother board interface. Having the contacts in such close proximity affects the electrical performance of the contacts. For example, interference from other contacts degrades the signals and diminishes the overall electrical performance of the connector. At higher data rates, the signal degradation is more problematic.
A need remains for a connector operable at high data rates with improved electrical performance.
In one embodiment, a card edge connector is provided including a housing having a mating end and a mounting end with a card edge slot configured to receive a circuit card therein. Signal contacts are held by the housing and have mating portions configured to be electrically coupled to corresponding signal pads of the circuit card and tail portions configured to be electrically coupled to a corresponding circuit board. Ground contacts are held by the housing and have tail portions configured to be electrically coupled to the circuit board, bifurcated portions extending from corresponding tail portion, first mating portions extending from corresponding bifurcated portions, and second mating portions extending from corresponding bifurcated portions.
Optionally, the mating portions of the signal contacts, the first mating portions of the ground contacts and the second mating portions of the ground contacts may be aligned within the card edge slot for electrical connection with the circuit card. The signal contacts may be arranged in pairs flanked by corresponding ground contacts. Optionally, M tail portions of the signal contacts may be provided while N tail portions of the ground contacts may be provided with M being approximately twice N.
Optionally, the card edge slot may extend longitudinally. The first and second mating portions of each ground contact may be longitudinally offset from the corresponding tail portion of such ground contact. The first and second mating portions of each ground contact may be laterally offset from the corresponding tail portion of such ground contact in a lateral direction generally perpendicular to the card edge slot. The tail portions of the signal contacts may be laterally offset from the corresponding mating portions of the signal contacts in an outer direction, and the tail portions of the ground contacts may be laterally offset from the corresponding first and second mating portions of the ground contacts in an inner direction generally opposite the outer direction.
In another embodiment, a card edge connector is provided including a housing having a mating end and a mounting end. The housing has a first side and a second side extending between the mating and mounting ends with a central plane between the first and second sides. The housing has a card edge slot extending along the central plane between the first and second sides that is configured to receive a circuit card therein. Signal contacts are held by the housing and arranged in a first group and a second group. The first group is between the central plane and the first side and the second group is between the central plane and the second side. The signal contacts have mating portions configured to be electrically coupled to corresponding signal pads of the circuit card and tail portions configured to be electrically coupled to a corresponding circuit board. The tail portions of the signal contacts are laterally offset away from the central plane from the mating portions. Ground contacts are held by the housing and arranged in a first group and a second group. The first group is between the central plane and the first side and the second group is between the central plane and the second side. The ground contacts have tail portions configured to be electrically coupled to the circuit board that are laterally offset toward the central plane. The ground contacts have bifurcated portions extending from corresponding tail portion. The ground contacts have first mating portions extending from corresponding bifurcated portions and second mating portions extending from corresponding bifurcated portions.
In a further embodiment, a connector system is provided including a circuit board having signal conductors and ground conductors and a card edge connector mounted to the circuit board. The card edge connector includes a housing having a card edge slot configured to receive a circuit card therein, signal contacts held by the housing, and ground contacts held by the housing. The signal contacts are electrically coupled to corresponding signal conductors. The ground contacts are bifurcated each having a single tail portion for being electrically coupled to corresponding ground conductors and a pair of mating portions for mating with the circuit card.
The card edge connector 102 includes a housing 110 having a mating end 112 and a mounting end 114. The mating end 112 is configured to receive the circuit card 106 therein. The mounting end 114 is configured to be mounted to the circuit board 104. The mating end 112 may be generally opposite the mounting end 114 defining a vertical card edge connector 102. In an alternative embodiment, the card edge connector 102 may be a right angle card edge connector 102 that receives the circuit card 106 in a horizontal direction such that the circuit card 106 is parallel to the circuit board 104.
The housing 110 holds a plurality of signal contacts 116 and a plurality of ground contacts 118. In an exemplary embodiment, the signal contacts 116 and ground contacts 118 are held in two rows within the housing 110 for mating with both sides of the circuit card 106. The signal contacts 116 and the ground contacts 118 are configured to be terminated to the circuit board 104. In an exemplary embodiment, the signal contacts 116 and the ground contacts 118 may be through-hole mounted to the circuit board 104. In an alternative embodiment, the signal contacts 116 and/or the ground contacts 118 may be surface mounted to the circuit board 104 rather than being through-hole mounted to the circuit board 104.
In an exemplary embodiment, the housing 110 includes one or more locating posts 120 extending from a mounting end 114. The locating posts 120 are configured to be received in corresponding openings (not shown) in the circuit board 104 to position the card edge connector 102 with respect to the circuit board 104.
The circuit card 106 includes a plurality of pads 122 that are configured to be electrically connected to corresponding signal contacts 116 or ground contacts 118. The pads 122 are arranged along an edge 124 of the circuit card 106. The edge 124 of the circuit card 106 is plugged into the card edge connector 102 when mated thereto. The circuit card 106 includes a keying feature 126 for orienting the circuit card 106 with respect to the card edge connector 102. In the illustrated embodiment, the keying feature 126 is a slot formed in the edge 124 that is offset forward one side of the circuit card 106.
In an exemplary embodiment, the housing 110 includes a keying feature 136 for orienting the circuit card 106 with respect to the card edge connector 102. In the illustrated embodiment, the keying feature 136 constitutes a bridge extending across the card edge slot 128. The keying feature 136 is received in the keying feature 126 (shown in
In an exemplary embodiment, the signal contacts 116 and ground contacts 118 are arranged in contact sets 140. Each contact set 140 includes one ground contact 118 and a pair of signal contacts 116. The contact sets 140 are arranged in parallel with each other. Any number of contact sets 140 may be used with the card edge connector 102, depending on the particular application and contact configuration desired for the particular application. In an exemplary embodiment, the signal contacts 116 within each contact set 140 define a differential pair carrying differential signals. The ground contacts 118 separate each differential pair from an adjacent differential pair. Each ground contact 118 includes a tail portion 142, a bifurcated portion 144, a first mating portion 146 and a second mating portion 148.
The tail portion 142 is configured to be terminated to the circuit board 104 (shown in
The bifurcated portion 144 extends from the tail portion 142. The bifurcated portion 144 transitions the ground contact 118 between the single tail portion 142 and the pair of the mating portions 146, 148. In an exemplary embodiment, the bifurcated portion is Y-shaped. Alternatively, the bifurcated portion 144 may be generally V-shaped. In other alternative embodiments, the bifurcated portion may be generally T-shaped, or may have other shapes depending on the particular desired spacing between the tail portion 142 and the mating portions 146, 148. The bifurcated portion 144 includes a first arm 150 extending between the tail portion 142 and the first mating portion 146. The bifurcated portion 144 includes a second arm 152 extending between the tail portion 142 and the second mating portion 148. The first and second arms 150, 152 are angled with respect to one another. Optionally, the first arm 150 and/or the second arm 152 may be angled with respect to the tail portion 142.
The first mating portion 146 extends between a base 154 and a tip 156. The base 154 extends from the bifurcated portion 144. The first mating portion 146, at the tip 156, is configured to be electrically coupled to a corresponding pad 122 (shown in
The second mating portion 148 includes a base 158 and a tip 160. The base 158 extends from the bifurcated portion 144. The second mating portion 148, at the tip 160, is configured to be electrically coupled to a corresponding pad 122 on the circuit card 106 when mated thereto. In an exemplary embodiment, the first mating portion 146 is generally parallel to the second mating portion 148.
Each signal contact 116 includes a tail portion 162 configured to be electrically coupled to the circuit board 104 and a mating portion 164 configured to be electrically coupled to a corresponding pad 122 on the circuit card 106. In an exemplary embodiment, each signal contact 116 includes a splayed portion 166 transitioning between the tail portion 162 and the mating portion 164. The splayed portion 166 longitudinally and/or laterally offsets the tail portion 162 from the mating portion 164. The splayed portion 166 transitions the tail portion 162 generally away from the tail portion 162 of the other signal contact 116 within the contact set 140. The tail portions 162 of the signal contacts 116 within each contact set 140 are positioned further from one another than the corresponding mating portions 164 of the signal contacts 116 of the contact set 140. Having greater separation of the tail portions 162 may provide a more desirable footprint for the card edge connector 102 for termination to the circuit board 104. By providing additional spacing between the tail portion 162 and the corresponding plated vias through the circuit board 104. The bifurcated portion 144 of the ground contact 118 provides space for the splayed portion 166 to transition the tail portions 162. In alternative embodiments, rather than having the splayed portions transitioning the tail portions 162 laterally, the tail portions 162 may remain in line with the mating portions 164.
In an exemplary embodiment, the tail portions 142, 162 of the ground and signal contacts 118, 116 transition laterally. For example, the tail portions 142 of the ground contacts 118 transition laterally inward in an inner direction 182 toward a central plane 138 of the housing 110. The central plane 138 is centered between the first and second sides 170, 172. The card edge slot 128 extends along the central plane 138. The first group 176 of signal and ground contact 116, 118 are on one side of the central plane 138 while the second group 178 of signal and ground contact 116, 118 are on the other side of the central plane 138. The tail portions 142 of the ground contacts 118 in the first group 176 are transitioned toward the central plane 138 and toward the tail portions 142 of the ground contacts 118 of the second group 178. The tail portions 162 of the signal contacts 116 are transitioned laterally outward in an outer direction 184 away from the central plane 138. The tail portions 162 of all the signal contacts 116 of the first group 176 are aligned in a single row. Optionally the tail portions 162 may be approximately aligned with the first side 170 of the housing 110. The tail portions 162 of all the signal contacts 116 of the second group 178 are aligned in a single row. Optionally the tail portions 162 may be approximately aligned with the second side 172 of the housing 110. In an alternative embodiment, rather than having the tail portions 142, 162 transition laterally, the tail portions 142, 162 may be in line in a single row.
The signal and ground contacts 116, 118 extend through openings 190 at the mounting end 114 of the housing 110 to an exterior of the housing 110. In the illustrated embodiment, the bifurcated portions 144 of the ground contacts 118 are provided exterior of the mounting end 114 of the housing 110. In the illustrated embodiment, the splayed portions 166 of the signal contacts 116 are provided exterior of the mounting end 114 of the housing 110. Optionally, the signal and ground contacts 116, 118 may transition laterally and/or longitudinally exterior of the mounting end 114 of the housing 110 to position the tail portions 142, 162 from mounting to the circuit board 104 (shown in
In an exemplary embodiment, all of the tail portions 162 of the signal contacts 116 in the first group 176 transition in the outer direction 184 from the first row 206. All of the tail portions 162 of the signal contacts 116 in the first group 176 are aligned along a first signal row 210 parallel to the first row 206. At the first row 206, the signal contacts 116 within each pair have a pitch 212. At the first signal row 210, the signal contacts 116 within each pair have a pitch 214 that is greater than the pitch 212. The splayed portions 166 (shown in
All of the tail portions 162 of the signal contacts 116 in the second group 178 are aligned along a second signal row 220 parallel to the second row 208. At the second row 208, the signal contacts 116 within each pair have a pitch 222. At the second signal row 220, the signal contacts 116 within each pair have a pitch 224 that is greater than the pitch 222. The splayed portions 166 (shown in
In an exemplary embodiment, all of the tail portions 142 of the ground contacts 118 in the first group 176 transition in the inner direction 182 from the first row 206. All of the tail portions 142 of the ground contacts 118 in the first group 176 are aligned along a first ground row 230 parallel to the first row 206. At the first row 206, the mating portions 146, 148 of the ground contacts 118 have a pitch 232. At the first ground row 230, only a single tail portion 142 is provided.
In an exemplary embodiment, all of the tail portions 142 of the ground contacts 118 in the second group 178 transition in the inner direction 182 from the second row 208. All of the tail portions 142 of the ground contacts 118 in the second group 178 are aligned along a second ground row 240 parallel to the second row 208. At the second row 206, the mating portions 146, 148 of the ground contacts 118 have a pitch 242. At the second ground row 240, only a single tail portion 142 is provided.
The carrier strip 250 has a frame 252 with supports 254 extending from the frame 252. The supports 254 extend between corresponding signal and ground contacts 116, 118 to attachment locations where the support 254 are attached to the corresponding signal and ground contacts 116, 118. In an exemplary embodiment, each signal contact 116 is attached to two different supports 254. Each ground contact 118 is attached to two different supports 254. The signal and ground contacts 116, 118 are adequately held by the supports 254 for assembly into the housing 110. Additionally, only one carrier strip 250 is needed to support the signal and ground contacts 116, 118. In an exemplary embodiment, the bifurcated portions 144 transition the ground contact 118 into a single tail portion 142. A space savings is provided by such configuration allowing room for the support 254 to extend from the frame 252 between the tail portions 142, 162 to corresponding attachment points with the signal and ground contacts 116, 118.
At the first and second rows 306, 308 of signal vias 302, the signal vias 302 within each pair have a pitch 314. The first pitch 314 may be approximately 1.5 mm. At the first and second rows 310, 312 of ground vias 304, the ground vias 304 have a second pitch 316. The second pitch 316 may be approximately 4.0 mm. A third pitch 318 is defined longitudinally between the signal vias 302 and the nearest ground via 304. The third pitch 318 may be approximately 1.25 mm. A fourth pitch 320 is defined laterally between the rows 306, 310 and the rows 308, 312. The fourth pitch 320 may be approximately 1.25 mm. Other dimensions are possible in alternative embodiments. Having a single ground via 304 between pairs of signal vias 302, as opposed to two ground vias 304 in each row 310 or 312, allows the signal vias 302 to be spread further apart from each other and allows the signal vias 302 to be spread further apart from the corresponding ground vias 304.
The footprint 400 includes an array of tuning vias 406 interspersed among the signal and ground vias 402, 404. The tuning vias 406 define ground conductors of the circuit board 104 and may be referred to as ground conductors 406. The tuning vias 406 are electrically grounded at the same electrical potential as the ground vias 404. The tuning vias 406 have a smaller diameter than the ground vias 404. While the ground vias 404 receive tail portions 142 of corresponding ground contacts 118, the tuning vias 406 do not receive any tails or pins, but rather are conductive vias extending through the circuit board 104.
The tuning vias 406 are positioned at predetermined positions relative to the signal vias 402 to affect the electrical performance of the signal lines. For example, spacings 408 may be defined between the tuning vias 406 and the signal vias 402. The spacings 408 may be varied across the footprint 400 rather than being uniform. The tuning vias 406 are positioned closer to the signal vias 402 than the ground vias 404 to maintain proper signal referencing to ground, such as to control impedance, return loss or other electrical characteristics. Any number of tuning vias 406 may be provided. The tuning vias 406 may surround the pairs of signal vias 402. The tuning vias 406 may be positioned between adjacent pairs of signal vias 402.
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.
