Cross-talk reduction in high speed electrical connectors

• US 6,988,902 B2
• Filed: 03/22/2005
• Issued: 01/24/2006
• Est. Priority Date: 11/14/2001
• Status: Expired due to Term

• Current Assignee: FCI Americas Technology Incorporated (FCI)
• Original Assignee: FCI Americas Technology Incorporated (FCI)
• Inventors: Houtz, Timothy W., Lemke, Timothy A., Smith, Stephen B., Shuey, Joseph B., Sercu, Stefaan Hendrik Josef, Winings, Clifford L., Hull, Gregory A.
• Primary Examiner(s): GUSHI, ROSS N
• Application Number:
  US11/087,047
• Publication Number:
  US 20050164555A1
• Time in Patent Office: 308 Days
• Field of Search: 439/79, 439/701, 439/941
• US Class Current: 439/79
• CPC Class Codes: H01R 12/724 containing contact members forming a right angle
• CPC Class Codes: H01R 13/6471 by special arrangement of ground and signal conductors, e.g. GSGS [Ground-Signal-Ground-Signal]
• CPC Class Codes: H01R 13/6477 by variation of dielectric properties
• CPC Class Codes: H01R 13/6587 for mounting on PCBs

Abstract

Lightweight, low-cost, high-density electrical connectors are disclosed that provide impedance-controlled, high-speed, low-interference communications, even in the absence of shields between the contacts, and that provide for a variety of other benefits not found in prior art connectors. An example of such an electrical connector may include a first signal contact positioned within a first array of electrical contacts and a second signal contact positioned within a second array of electrical contacts that is adjacent to the first linear array. Either of the signal contacts may be a single-ended signal conductor, or one of a differential signal pair. The connector may be devoid of shields between the signal contacts, and of ground contacts adjacent to the signal contacts.

Claims

1. An electrical connector comprising:

three electrical contacts, each of which defines, in cross-section at a respective mating end thereof, an edge and a broadside that is longer than the edge, wherein the three electrical contacts are positioned edge-to-edge along a first linear array of electrical contacts, wherein two adjacent electrical contacts define a first differential signal pair and the remaining electrical contact defines a ground contact;

a second differential signal pair and a second ground contact positioned along a second linear array of electrical contacts that is adjacent to the first linear array of electrical contacts; and

a third differential signal pair and a third ground contact positioned along a third linear array of electrical contacts that is adjacent to the second linear array of electrical contacts,

wherein (i) the electrical connector is devoid of shields between the first, second, and third linear arrays of electrical contacts;

(ii) the second differential signal pair is offset by a row pitch or less along the second linear array of electrical contacts with respect to each of the first differential signal pair and the third differential signal pair; and

(iii) a first gap is defined between the two adjacent electrical contacts of the first differential signal pair and the first gap is equal to a second gap defined between one of the contacts of the first differential signal pair and the ground contact.

2. The electrical connector of claim 1, wherein the ground contact extends from a mating face of the electrical connector, and extends farther than the electrical contacts that comprise the first differential signal pair.

3. The electrical connector of claim 1, wherein the impedance of the first differential signal pair is about 100±

10 ohm at a data rate of about 1 Gigabit/sec and about 100±

10 ohm at a data rate of about 10 Gigabits/sec.

4. The electrical connector assembly of claim 1, wherein the first linear array of electrical contacts and the second linear array of electrical contacts extend along imaginary centerlines that are spaced apart about two millimeters or less.

5. The electrical connector assembly of claim 1 further comprising two electrical contacts arranged in the third linear array of electrical contacts, wherein the two electrical contacts each terminate with a corresponding fusible mounting element.

6. The electrical connector assembly of claim 1, wherein a differential signal in the first differential signal pair produces an electric field having a first electric field strength in the gap and a second electric field strength near the second differential signal pair, wherein the second electric field strength is lower than the first electric field strength.

7. The electrical connector assembly of claim 1, having a row pitch of about 1.4 mm.

8. The electrical connector assembly of claim 1, having a column pitch of about 2.0 mm or less.

9. The electrical connector assembly of claim 1, having a card pitch of about 25 mm.

10. The electrical connector assembly of claim 1, comprising a housing though which the contacts extend.

11. The electrical connector assembly of claim 1, having a near-end cross talk of less than about three percent at an initial rise time of about 40 picoseconds.

12. The electrical connector assembly of claim 1, having a far-end cross talk of less than about four percent at an initial rise time of about 40 picoseconds.

13. The electrical connector assembly of claim 1, having a contact density of about 63.5 mated signal pairs per linear inch.

14. The electrical connector assembly of claim 1, having a contact density of more than about 63.5 mated signal pairs per linear inch.

15. The electrical connector assembly of claim 1, having an insertion loss of less than about 0.7 dB at 5 GHz.

16. The electrical connector assembly of claim 1, wherein the first differential signal pair has an impedance of about 100±

10 ohm at a data rate of about 1 Gigabit/sec and at a data rate of about 10 Gigabits/sec.

17. The electrical connector assembly of claim 1, wherein the first differential signal pair is positioned along a first contact column and the second differential signal pair is positioned along a second contact column.

18. The electrical connector assembly of claim 17, wherein the first column is offset from the second column by a distance such that cross-talk is reduced between the first and second differential signal pairs.

19. The electrical connector assembly of claim 1, further comprising a first lead assembly and second lead assembly adjacent to the first lead assembly, wherein the first differential signal pair is disposed on the first lead assembly and the second differential signal pair is disposed on the second lead assembly.

20. The electrical connector assembly of claim 19, wherein the mating ends of the electrical contacts that define the first differential signal pair are edge-coupled.

21. The electrical connector assembly of claim 1, comprising a housing though which the contacts extend, wherein the housing is filled at least in part with a dielectric material that electrically insulates the contacts.

22. The electrical connector assembly of claim 21, wherein the dielectric material is air.

23. The electrical connector assembly of claim 22, wherein the connector is a right angle, ball grid assembly connector.