Printed wiring boards and communication connectors having series inductor-capacitor crosstalk compensation circuits that share a common inductor
Printed wiring boards for communications connectors are provided that include a mounting substrate having at least first through third input terminals and first through third output terminals. A first conductive path connects the first input terminal to the first output terminal, a second conductive path connects the second input terminal to the second output terminal and a third conductive path connects the third input terminal to the third output terminal. A first inductor and a first capacitor are coupled between the first conductive path and the second conductive path, where the first inductor and the first capacitor are arranged in series to provide a first series inductor-capacitor circuit. A second capacitor is coupled between the third conductive path and the second conductive path through the first inductor to provide a second series inductor-capacitor circuit that shares the inductor of the first series inductor-capacitor circuit. Communications connectors that include such wiring boards or equivalent structures are also provided.
1. A communications connector, comprising:
a plurality of conductive paths, each of which connects a respective one of a plurality of input terminals to a respective one of a plurality of output terminals, wherein each of the conductive paths is paired with another of the conductive paths, and each of the pairs are configured to transmit a differential signal through the connector;
a first capacitor and a first inductor coupled in series between a first conductive path of a first of the differential pairs and a first conductive path of a second of the differential pairs to provide a first series inductor-capacitor circuit between the first conductive path of the first of the differential pairs and the first conductive path of the second of the differential pairs; and
a second capacitor coupled between a first conductive path of a third of the differential pairs and a first node that is located between the first capacitor and the first inductor to provide a second series inductor-capacitor circuit between the first conductive path of the third of the differential pairs and the first conductive path of the second of the differential pairs.
2. The communications connector of claim 1 , further comprising a second inductor disposed in series between the second capacitor and the first node that is part of the second series inductor-capacitor circuit.
3. The communications connector of claim 2 , further comprising a crosstalk compensation circuit between the first of the differential pairs and the third of the differential pairs that is designed to at least partly compensate for crosstalk that passes between the first of the differential pairs and the third of the differential pairs via the first capacitor, the second capacitor and the second inductor.
4. The communications connector of claim 2 , wherein the communications connector comprises a communications jack, wherein the conductive paths are aligned in a generally side-by-side array in a plug-jack mating region of the connector, and wherein one of the conductive paths of the third differential pair is on the outside of the array in the plug-jack mating region.
5. The communications connector of claim 2 , wherein a capacitance of the first capacitor exceeds a capacitance of the second capacitor by at least fifty percent.
6. The communications connector of claim 2 , wherein the resonant frequency of the first series inductor-capacitor circuit is within 25% of the resonant frequency of the second series inductor-capacitor circuit.
7. A communications connector, comprising:
a first input terminal, a first output terminal, and a first conductive path extending from the first input terminal to the first output terminal;
a second input terminal, a second output terminal, and a second conductive path extending from the second input terminal to the second output terminal;
a third input terminal, a third output terminal, and a third conductive path extending from the third input terminal to the third output terminal;
a fourth input terminal, a fourth output terminal, and a fourth conductive path extending from the fourth input terminal to the fourth output terminal;
a fifth input terminal, a fifth output terminal, and a fifth conductive path extending from the fifth input terminal to the fifth output terminal;
a sixth input terminal, a sixth output terminal, and a sixth conductive path extending from the sixth input terminal to the sixth output terminal;
a seventh input terminal, a seventh output terminal, and a seventh conductive path extending from the seventh input terminal to the seventh output terminal;
an eighth input terminal, an eighth output terminal, and an eighth conductive path extending from the eighth input terminal to the eighth output terminal;
a first capacitor and a first inductor coupled in series between one of the fourth or fifth conductive paths and one of the third or sixth conductive paths;
a second capacitor coupled between one of the first, second, seventh or eighth conductive paths and a node located between the first capacitor and the first inductor;
wherein the fourth and fifth conductive paths comprise a first differential pair of conductive paths;
wherein the first and second conductive paths comprise a second differential pair of conductive paths;
wherein the third and sixth conductive paths comprise a third differential pair of conductive paths; and
wherein the seventh and eighth conductive paths comprise a fourth differential pair of conductive paths.
8. The communications connector of claim 7 , further comprising a second inductor disposed in series between the second capacitor and a node located between the first capacitor and the first inductor.
9. The communications connector of claim 7 , wherein the first capacitor and the first inductor comprise a first series inductor-capacitor circuit and wherein the second capacitor, the second inductor and the first inductor comprise a second series inductor-capacitor circuit.
10. The communications connector of claim 7 , wherein the first through eighth conductive paths are aligned in numerical order in a substantially side-by-side relationship in a plug jack mating region of the connector.
11. The communications connector of claim 7 , wherein a capacitance of the first capacitor exceeds a capacitance of the second capacitor by at least fifty percent.
12. A communications connector, comprising:
a housing;
a printed wiring board that is mounted at least partially within the housing, the printed wiring board having at least first through third input terminals and first through third output terminals;
a first conductive path that connects the first input terminal to the first output terminal;
a second conductive path that connects the second input terminal to the second output terminal;
a third conductive path that connects the third input terminal to the third output terminal;
a first inductor and a first capacitor coupled between the first conductive path and the second conductive path, where the first inductor and the first capacitor are arranged in series to provide a first series inductor-capacitor circuit; and
a second capacitor coupled between the third conductive path and the second conductive path through the first inductor.
13. The communications connector of claim 12 , further comprising a second inductor that is coupled between the second capacitor and the first inductor.
14. The communications connector of claim 13 , wherein the second capacitor, the second inductor and the first inductor form a second series inductor-capacitor circuit.
15. The communications connector of claim 14 , wherein a resonant frequency of at least one of the first and second series inductor-capacitor circuits is set in the range of about 750 MHz to about 1000 MHz.
16. The communications connector of claim 13 , wherein at least one of the first inductor or the second inductor comprises a conductive trace that is on and/or within the printed wiring board that includes self-coupling segments that are immediately adjacent to each other and that have the same instantaneous current direction.
17. The communications connector of claim 16 , wherein the self coupling segments comprise a portion of the conductive path that has a spiral shape.
18. The communications connector of claim 12 , further comprising:
a fourth conductive path that together with the second conductive path forms a differential pair of conductive paths for carrying a differential signal; and
a crosstalk compensation circuit between the first conductive path and the fourth conductive path that generates crosstalk having a first polarity;
wherein the first polarity is generally opposite the polarity of the crosstalk generated by the first series inductor-capacitor circuit.
19. The communications connector of claim 13 , wherein a capacitance of the first capacitor exceeds a capacitance of the second capacitor by at least fifty percent.
20. The communications connector of claim 14 , wherein the resonant frequency of the first series inductor-capacitor circuit is within 25% of the resonant frequency of the second series inductor-capacitor circuit.