High performance cable termination
A cable assembly comprising a connector with a termination that enables high density and high signal integrity. Shields of cables are terminated to a paddle card via a conductive structure attached to a surface of the paddle card. The signal conductors of the cables are terminated to pads on the paddle card that are exposed within openings of the conductive structure. Such a structure creates a ground structure per cable that provides low insertion loss and low crosstalk, even when multiple cables are aligned side by side and terminated in one or more rows. The cables may be drainless, enabling a large number of cables, such as eight cables, to be packed within the width of a paddle card specified in high density standards such as QSFP-DD or OSFP. The cables may nonetheless have large diameter signal conductors, enabling 2.5 or 3 meter assemblies with less than 17 dB insertion loss.
1. A paddle card for use in a cable connector terminating a plurality of cables, the paddle card comprising:
a surface on a first side and a plurality of sets of pads arranged on the surface in at least a first row and a second row, each set of the plurality of sets of pads being associated with a respective cable of a plurality of cables and comprising:
a signal pad; and
a ground pad;
a first plurality of discrete conductive members, each of the first plurality of discrete conductive members configured for mechanical connection to a shield of a respective cable of the plurality of cables associated with a set of pads in the first row by at least partially encircling the cable; and
a second plurality of discrete conductive members, each of the second plurality of discrete conductive members configured for mechanical connection to a shield of a respective cable of the plurality of cables associated with a set of pads in the second row by at least partially encircling the cable, wherein:
the first plurality of discrete conductive members and the second plurality of discrete conductive members are electrically connected to the ground pads of the plurality of sets of pads.
2. The paddle card of claim 1 , wherein:
the paddle card further comprises at least one conductive sheet mounted against the surface and electrically connected to the ground pads of the plurality of sets of pads; and
each of the first plurality of discrete conductive members and the second plurality of discrete conductive members is connected to a respective conductive sheet of the at least one conductive sheet such that the first plurality of discrete conductive members and the second plurality of discrete conductive members are connected to the ground pads through the at least one conductive sheets.
3. The paddle card of claim 2 , wherein:
each of the first plurality of discrete conductive members and the second plurality of discrete conductive members is integrally formed with the respective conductive sheet.
4. The paddle card of claim 2 , wherein:
the at least one conductive sheet comprises:
a first conductive sheet connected to ground pads in a plurality of sets of ground pads in the first row; and
a second conductive sheet connected to ground pads in a plurality of sets of ground pads in the second row.
5. The paddle card of claim 2 , wherein:
each conductive sheet of the at least one conductive sheet comprises a plurality of openings aligned with a respective plurality of regions on the surface of the paddle card; and
at each of the plurality of regions on the surface of the paddle card, signal conductors of a respective cable of the plurality of cables are exposed over the region for electrically connecting to signal pads of the paddle card.
6. The paddle card of claim 1 in combination with:
a connector housing, wherein the paddle card is disposed within the connector housing;
the plurality of cables; and
a stabilizing member disposed within the connector housing and configured to hold at least some of the plurality of cables relative to the paddle card.
7. The paddle card of claim 1 , wherein:
the paddle card has a first end and a second end;
the plurality of sets of pads are disposed proximate the first end, and
a plurality of sets of contact pads are disposed proximate the second end and electrically connected with respective sets of the plurality of sets of pads within the paddle card.
8. The paddle card of claim 7 , wherein the paddle card is configured for an OSFP standard.
9. The paddle card of claim 1 , wherein:
each set of the plurality of sets of pads comprises a pair of signal pads associated with a pair of signal conductors of the respective cable; and
in at least some of the plurality of sets of pads, the ground pad separates the pair of signal pads from the signal pads of an adjacent set of pads of the plurality of sets of pads.
10. A connector, comprising:
a plurality of cables, each of the plurality of cables comprising at least one signal conductor and a shield around the at least one signal conductor;
a paddle card comprising:
a surface on a first side of the paddle card;
a ground structure comprising at least one ground pad on the surface; and
a plurality of signal pads on the surface in at least a first row along a row direction, wherein the signal conductors of the plurality of cables are coupled to respective pads of the plurality of signal pads; and
a conductive structure connecting the shields of the plurality of cables to the ground structure in a plurality of locations, the conductive structure comprising:
a conductive sheet mounted on the surface, the conductive sheet electrically connected to the at least one ground pad in the plurality of locations; and
a plurality of portions attached to the conductive sheet, each of the plurality of portions disposed over a respective cable of the plurality of cables such that the shield of the respective cable is between the conductive sheet and the respective portion and electrically coupled to the conductive sheet and the respective portion, wherein the plurality of portions are on the first side of the paddle card and aligned with one another in the row direction.
11. The connector of claim 10 , wherein each of the plurality of cables is pressed between the conductive sheet and a respective portion of the plurality of portions.
12. The connector of claim 11 , wherein the conductive sheet is soldered to the at least one ground pad in the plurality of locations.
13. The connector of claim 10 , wherein the paddle card further comprises a ground layer parallel to the surface, and the ground layer electrically connected to the at least one ground pad.
14. The connector of claim 10 , further comprising a stabilizing member configured to hold the at least some of the plurality of cables relative to the paddle card.
15. The connector of claim 10 , wherein paddle card has a first end and a second end, with the plurality of signal pads disposed proximate the first end, and with a plurality of contact pads disposed proximate the second end and electrically connected with the plurality of signal pads.
16. The connector of claim 15 , wherein the paddle card is configured for an OSFP standard.
17. The connector of claim 10 , wherein:
the at least one signal conductor for each of the plurality of cables is a pair of signal conductors;
the plurality of signal pads comprises pairs of signal pads with each pair associated with a pair of signal conductors of a respective cable of the plurality of cables; and
the at least one ground pad comprises a plurality of ground pads with a ground pad of the plurality of ground pads separating adjacent pairs of pairs of signal pads.
18. A connector assembly, comprising:
a first plurality of cables, each of the first plurality of cables comprising a signal conductor and a shield;
a second plurality of cables, each of the second plurality of cables comprising a signal conductor and a shield;
a paddle card comprising:
a first surface on a first side of the paddle card and a second surface on a second side of the paddle card;
a ground structure comprising at least one ground pad on the first surface and at least one ground pad on the second surface; and
a first plurality of signal pads on the first surface in at least a first row along a row direction, wherein the signal conductors of the first plurality of cables are coupled to respective pads of the first plurality of signal pads; and
a second plurality of signal pads on the second surface in at least a second row along a row direction, wherein the signal conductors of the second plurality of cables are coupled to respective pads of the second plurality of signal pads;
a first conductive structure connecting the shields of the first plurality of cables to the ground structure in a first plurality of locations, the first conductive structure comprising:
a first conductive sheet mounted on the first surface, the first conductive sheet electrically connected to the at least one ground pad in the first plurality of locations; and
a first plurality of portions attached to the first conductive sheet, each of the first plurality of portions disposed over a respective cable of the first plurality of cables such that the shield of the respective cable is between the first conductive sheet and the respective portion and electrically coupled to the first conductive sheet and the respective portion, wherein the first plurality of portions are on the first side of the paddle card and aligned with one another in the row direction; and
a second conductive structure connecting the shields of the second plurality of cables to the ground structure in a second plurality of locations, the second conductive structure comprising:
a second conductive sheet mounted on the second surface, the second conductive sheet electrically connected to the at least one ground pad in the second plurality of locations; and
a second plurality of portions attached to the second conductive sheet, each of the second plurality of portions disposed over a respective cable of the second plurality of cables such that the shield of the respective cable is between the second conductive sheet and the respective portion and electrically coupled to the second conductive sheet and the respective portion, wherein the second plurality of portions are on the second side of the paddle card and aligned with one another in the row direction.
19. The connector of claim 18 , wherein:
the first plurality of portions and the first conductive sheet are positioned relative to one another so as to hold the first plurality of cables and connect the shields of the first plurality of cables to the ground structure; and
the second plurality of portions and the second conductive sheet are positioned relative to one another so as to hold the second plurality of cables and connect the shields of the second plurality of cables to the ground structure.
20. The connector of claim 19 , wherein:
the first conductive sheet is soldered to a ground pad of the at least one ground pad on the first surface; and
the second conductive sheet is soldered to a ground pad of the at least one ground pad on the second surface.
21. The connector of claim 18 , further comprising:
a stabilizer holding the first plurality of cables and the second plurality of cables relative to the paddle card.
22. The connector of claim 18 , wherein the paddle card further comprises:
a first end, wherein the first plurality of signal pads and the second plurality of signal pads are disposed proximate the first end;
a second end;
a first plurality of contact pads disposed on the first surface proximate the second end and electrically connected with respective pads of the first plurality of pads within the paddle card; and
a second plurality of contact pads disposed on the first surface proximate the second end and electrically connected with respective sets of the first plurality of sets of pads within the paddle card.
23. The connector of claim 22 , wherein the paddle card is configured for an OSFP standard.
24. The connector of claim 18 , wherein:
the first conductive sheet spans the first row.
25. The connector of claim 18 , wherein:
the first conductive sheet spans a portion of the first row; and
the connector comprises a further conductive sheet mounted on the first surface, aligned with the first conductive sheet in the row direction, the further conductive sheet coupling shields of further cables to the ground structure of the paddle card.