Flexible cable for high-speed interconnect

• US 7,148,428 B2
• Filed: 09/27/2004
• Issued: 12/12/2006
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Dabral, Sanjay, Meier, Pascal C. H.
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): Semenenko, Yuriy
• Application Number:
  US10/950,827
• Publication Number:
  US 20060067066A1
• Time in Patent Office: 806 Days
• Field of Search: 174/260, 174/261, 361/785, 361/790, 361/788, 361/789, 361791-794
• US Class Current: 174/260
• CPC Class Codes: G06F 1/184 Mounting of motherboards
• CPC Class Codes: G06F 1/185 Mounting of expansion boards
• CPC Class Codes: G06F 1/186 Securing of expansion boards in correspondence to slots provided at the computer enclosure
• CPC Class Codes: G06F 1/189 Power distribution
• CPC Class Codes: H01R 12/79 connecting to rigid printed circuits or like structures
• CPC Class Codes: H05K 1/14 Structural association of two or more printed circuits providing electric connection to or between printed circuits H05K1/11, H01R12/00
• CPC Class Codes: H05K 1/147 at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 2201/044 Details of backplane or midplane for mounting orthogonal PCBs
• CPC Class Codes: H05K 2201/10356 Cables
• CPC Class Codes: H05K 2201/10492 Electrically connected to another device mounted components directly electrically connected to each other H05K2201/1053
• CPC Class Codes: H05K 2201/10704 Pin grid array [PGA]
• CPC Class Codes: H05K 2201/2027 Guiding means, e.g. for guiding flexible circuits
• CPC Class Codes: H05K 3/222 Completing of printed circuits by adding non-printed jumper connections printed jumper connections H05K3/4685
• CPC Class Codes: H05K 3/305 Affixing by adhesive
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

A system and method are disclosed in which flex cables are affixed to PCBs, for providing high-speed signaling paths between ICs disposed upon the PCBs. The flex cables are fixably attached to the PCBs so as to substantially mimic their structural orientation. Where the configuration includes more than one PCB, the flex cables include multiple portions which are temporarily separable from one another and from the die, using flex-to-flex and flex-to-package connectors, allowing field maintenance of the configuration. By routing the high-speed signals between ICs onto the flex cable, single-layer PCBs can be used for non-critical and power delivery signals, at substantial cost savings. By disposing the flex cables onto the PCB rather than allowing the cables to float freely, the configuration is thermally managed as if the signals were on the PCB and cable routing problems are avoided.

Claims

1. A system, comprising:

a flex cable, to transmit signals between a first integrated circuit and a second integrated circuit, the flex cable comprising a signaling path between the integrated circuits, the first integrated circuit being disposed upon a printed circuit board and the second integrated circuit being disposed upon a second printed circuit board, the printed circuit boards comprising signaling traces, wherein the signaling path is not coupled to the signaling traces, the flex cable comprising;

a first portion, having a flattened surface, the flattened surface being substantially parallel to and proximately attached to the printed circuit board;

a flex-to-package connector fixably attached to the printed circuit board, to couple the first portion to the first integrated circuit;

a second portion, coupled to the first portion by a flex-to-flex connector, the second portion having a second flattened surface, the second flattened surface being substantially parallel to and proximately attached to the second printed circuit board; and

a second flex-to-package connector to couple the second portion to the second integrated circuit; and

an anchor to couple the printed circuit board to the second printed circuit board, the anchor further transmitting second signals between the printed circuit board and the second printed circuit board, wherein the second signals are not transmitted over the signaling path.

2. The system of claim 1, wherein the flex-to-package connector comprises a controlled collapsible chip connect to couple the first portion of the flex cable to the first integrated circuit.

3. The system of claim 1, wherein the flex-to-package connector comprises a high-speed portion of a two-part socket element to couple the first portion of the flex cable to the first integrated circuit.

4. The system of claim 1, wherein the flex-to-package connector couples the first portion to a die of the first integrated circuit.

5. The system of claim 1, wherein the flex-to-package connector couples the first portion to a substrate of the first integrated circuit.

6. The system of claim 1, wherein the first portion is attached to the printed circuit board using an adhesive material.

7. The system of claim 1, wherein the first portion is attached to the printed circuit board using a solder bond.

8. The system of claim 1, wherein the first portion is tied to the printed circuit board.

9. A system to transmit a signal between integrated circuits, the system comprising:

a flex cable affixed to a printed circuit board, the flex cable comprising a signaling path to transmit the signal between the integrated circuits, the printed circuit board comprising a signaling trace, wherein the signaling path is not coupled to the signaling trace;

a flex-to-package connector, to couple the flex cable to a package located on the printed circuit board, the package comprising an integrated circuit;

a second flex cable affixed to a second printed circuit board, the second flex cable comprising a second signaling path to transmit the signal between the integrated circuits;

the second printed circuit board comprising a second signaling trace, wherein the signaling path is not coupled to the second signaling trace;

a flex-to-flex connector affixed to the printed circuit board, the flex-to-flex connector to couple the flex cable to the second flex cable when closed and to release the flex cable from the second flex cable when opened; and

a second flex-to-package connector, to couple the second flex cable to a second package located on the second printed circuit board, the second package comprising a second integrated circuit;

wherein the printed circuit board is separable from the second printed circuit board by opening the flex-to-flex connector to uncouple the flex cable from the second flex cable.

10. The system of claim 9, further comprising an anchor to structurally support the second printed circuit board on the printed circuit board, wherein the anchor further provides an electrical connection for transmission of low-speed signals between the two printed circuit boards.

11. The system of claim 10, wherein the second printed circuit board includes a hole through which the second flex cable is threaded to form a connection between the flex-to-flex connector and the second flex-to-package connector.

12. The system of claim 9, wherein the flex-to-package connector comprises a controlled collapsible chip connect to couple the flex cable to the package.

13. The system of claim 9, wherein the flex-to-package connector comprises a high-speed portion of a two-part socket element to couple the flex cable to the package.

14. The system of claim 9, wherein the flex-to-package connector couples the flex cable to a die of the integrated circuit.

15. The system of claim 9, further comprising:

a third flex-to-package connector, to couple a third flex cable to the package located on the printed circuit board;

wherein the flex cable and the third flex cable transmit signals to the package.

16. A system, comprising:

first and second packages comprising integrated circuits, the first and second packages being connected to first and second printed circuit boards, respectively, wherein the first and second printed circuit boards are anchored to a motherboard; and

a flex cable to transmit signals between a first integrated circuit and a second integrated circuit, the flex cable comprising a signaling path between the integrated circuits, the first integrated circuit being disposed upon the first printed circuit board and the second integrated circuit being disposed upon the second printed circuit board, the printed circuit boards comprising signaling traces, wherein the signaling path is not coupled to the signaling traces, the flex cable comprising;

first and second flex portions affixed to the first and second printed circuit boards, respectively, the first and second flex portions each having a flattened surface, wherein each flattened surface is substantially parallel to and proximately attached to the respective printed circuit board;

a third flex portion affixed to the motherboard, the third flex portion having a second flattened surface, wherein the second flattened surface is substantially parallel to and proximately attached when affixed to the motherboard;

first and second flex-to-package connectors to couple the first and second flex portions to the first and second packages, respectively; and

first and second flex-to-flex connectors to couple the first and second flex portions, respectively, to the third flex portion;

wherein the first and second printed circuit boards are removable from the motherboard by disengaging the first and second flex-to-flex connectors.

17. The system of claim 16, wherein the first flex-to-package connector comprises a controlled collapsible chip connect to couple the first flex portion to the first package.

18. The system of claim 17, wherein the second flex-to-package connector comprises a high-speed portion of a two-part socket element to couple the second flex portion to the second package.

19. The system of claim 16, wherein the first flex-to-package connector couples the first flex portion to a die of the first package.

20. The system of claim 16, wherein the first and second printed circuit boards are single-layer boards.

21. The system of claim 16, wherein the first flex portion is affixed to the first printed circuit board using an adhesive material.

22. The system of claim 21, wherein the second flex portion is affixed to the second printed circuit board using a solder bond.

23. The system of claim 22, wherein the third flex portion is affixed to the motherboard using tie-downs.

24. A method, comprising:

identifying a pair of integrated circuits between which high-speed signaling is desired, the pair of integrated circuits including a first integrated circuit and a second integrated circuit;

identifying a first and a second printed circuit board connecting between the integrated circuit pair;

obtaining flex cable portions and permanently affixing each flex cable portion to an associated printed circuit board, the flex cable, to transmit signals between the first integrated circuit and the second integrated circuit, the flex cable comprising a signaling path between the integrated circuits, the first integrated circuit being disposed upon the printed circuit board and the second integrated circuit being disposed upon the second printed circuit board, the printed circuit boards comprising signaling traces, wherein the signaling path is not couples to the signaling traces;

connecting a first flex-to-package connector to the first integrated circuit;

connecting a second flex-to-package connector to the second integrated circuit; and

attaching flex cable portions between printed circuit boards using a second number of flex-to-flex connectors, wherein the second number is one less than the number.

25. The method of claim 24, further comprising:

boring a hole in one of the printed circuit boards and threading the associated flex cable through the hole.

26. The method of claim 24, further comprising:

disengaging one of the flex-to-flex connectors such that the flex cables coupled thereto are separated; and

separating the associated printed circuit boards.