High speed bypass cable for use with backplanes
A cable bypass assembly is disclosed for use in providing a high frequency transmission line that connect a chip package on a circuit board to connector spaced apart from the chip package. The bypass cable assembly has a structure that allows for low loss between the chip package and the connector. Multiple cables can be used to provide a number of differentially coupled channels.
1. A bypass cable assembly, comprising:
a first connector with a plurality of wafers and a plurality of terminals positioned in each of the wafers, the plurality of terminals positioned in a row and including signal terminals and ground terminals, the signal terminals being arranged in pairs and at least one of the ground terminals positioned between pairs of the signal terminals, wherein the terminals include contacts that extend from the respective wafer in a cantilevered manner;
a plurality of cables including a first and second cable, each of the plurality of cables including an insulative body portion with a pair of associated signal conductors extending lengthwise through the insulative body portion, the signal conductors of each pair being spaced apart, each cable of the plurality of cables including a ground shield that extends around the insulative body portion, the ground shield and signal conductors having opposing first and second free ends, wherein the first free ends are terminated to the signal and ground terminals in the first connector; and
a second connector mounted to the second free end, the second connector configured to connect the signal terminals in the first connector to circuit traces adjacent a chip package.
2. The bypass cable assembly of claim 1 , wherein the bypass cable assembly is configured to support 10 GHz signaling.
3. The bypass cable assembly of claim 2 , wherein the bypass cable assembly is configured to support 15 GHz signaling.
4. The bypass cable assembly of claim 2 , wherein the second connector includes terminals that are configured to be press-fit into a vias.
5. The bypass cable assembly of claim 2 , wherein a second connector includes terminals that are connected to the signal conductors in the cables and provide an electrical connection to the circuit traces.
6. The bypass cable assembly of claim 1 , wherein the first connectors is arranged so that the pair of signal contacts have ground contacts on both sides of the pair of signal contacts and the ground shield is electrically connected to the ground contacts on both sides of the pair of signal contacts.
7. A bypass connector, comprising:
a plurality of wafers formed of an insulative material, the wafers having a first side adjacent a mating area and a second side adjacent a termination area;
a plurality of terminals supported by each of the wafers, each terminal including a mating portion disposed in the mating area, the mating portions extending in a cantilevered manner from the first side and further including a tail portion disposed in the termination area, the plurality of terminals including signal terminals and ground terminals, the plurality of terminals supported by wafer of the plurality of wafers being arranged in a row of terminals and configured so the signal terminals are arranged in pairs and at least one of the ground terminal is positioned between pairs of signal terminals; and
a plurality of wires extending from the body toward another connector, each wire including a pair of signal conductors extending lengthwise through an insulative body and a grounding shield extending over an exterior surface of the insulative body, wherein the pair of signal conductors connected to the signal terminals and the grounding shield is connected to the ground terminals.
8. The bypass connector claim 7 , wherein the bypass cable assembly is configured to support 10 GHz signaling.
9. The bypass connector of claim 8 , wherein the plurality of wafers includes a first wafer and a second wafer that are adjacent, the first and second wafers configured so that the plurality of terminals in the first wafer are offset with respect to the plurality of terminals in the second wafer.
10. The bypass connector of claim 8 , further comprising a commoning member, the commoning member electrically connecting ground terminals in the plurality of wafers.
11. The bypass connector of claim 8 , wherein the bypass connector is configured to support 15 GHz signaling.
12. The bypass connector claim 8 , wherein the ground terminals are wider than the signal terminals.
13. The bypass connector of claim 8 , wherein signal conductors have a first spacing and the signal terminals have a second spacing and the second spacing is approximately between 1 and 2.5 times the first spacing.
14. The bypass connector of claim 8 , wherein each wafer of the plurality of wafers has a plurality of openings between the first and second side that expose the signal terminals to air.
15. The bypass connector of claim 8 , wherein the tails portions of the signal terminals are soldered or welded to the signal conductors in the termination area.
16. The bypass connector of claim 15 , wherein connection between the tail portions and signal conductors is covered in plastic.