Methods and apparatus for shielded and grounded cable system
地域：
AZ
AZ Scottsdale
摘要
Methods and apparatus for a shielded and grounded cable assembly include a coaxial cable assembly having a uniform spacing between cables to pre-align the cable assembly in an array corresponding to a connection layout of at a source end. The cable assembly includes a plurality of coaxial cables with exposed shields that are commonly grounded to a drain wire. The cable assembly may also be configured to be connected vertically/perpendicularly to a ball grid array or edge connected to a circuit board.
說明書
Micro sensing devices such as CMOS imaging sensors, arrays, or cameras require small form factors that inherently create installation and manufacturing concerns for discrete cable or coaxial cable termination. For example, devices such as CMOS imaging sensors, arrays or cameras typically have a ball grid array to facilitate the signal transfers to or from the device and/or to provide power. However, because these types of devices have size constraints on the order of 3 millimeters or less, cable design and proper termination of the cable at the device can be problematic.
Common methods of terminating shielded or coaxial cables to ball grid arrays (BGA) or other CMOS based circuit or substrate may require the use of a jumper cable or wire that is connected on a first end to a shield of any wire to a ground connection on the BGA or substrate on a second end. More simply, a jumper wire is a separate wire that is not part of the coaxial cable but is required to provide an adequate ground. Multiple jumper wires may be required in cable assemblies that incorporate more than one coaxial cable. These jumper wires may be on the nominal order of a few millimeters in length and create a manufacturing concern since connecting such a small length of wire within the space constraints of the assembly requires precision slowing down the manufacturing process and potentially leading to excessive manufacturing efficiencies or assembly quality problems.
Further, the use of jumper wires increases the required termination region/distance and/or a corresponding outer diameter of the termination. This may lead to a situation where the outer diameter of the termination or the length of the termination region exceeds an allowed size constraint for a particular device type or application.
權利要求
The invention claimed is:1. A cable assembly for connecting to a source device having a connection layout including a ground connection, comprising:an outer jacket; a first and a second coaxial cable disposed within the outer jacket, wherein:each coaxial cable comprises an exposed shield; and the exposed shield of the first coaxial cable is in contact with the exposed shield of the second coaxial cable; and a single drain wire disposed within the outer jacket coextensively with the first and second coaxial cables, wherein the drain wire is in contact with the exposed shield of at least one of the first and second coaxial cables, wherein the first and second coaxial cables and the drain wire are arranged in an array configured to pre-align the first and second coaxial cables and the drain wire to the connection layout of the source device to allow the drain wire to connect to the ground connection on the source device and act as a common ground for the first and second coaxial cables. 2. A cable assembly according to claim 1 , further comprising a third coaxial cable disposed within the outer jacket, wherein:the third coaxial cable comprises an exposed shield; and the exposed shield of the third coaxial cable is in contact with the exposed shield of at least one of the first and second coaxial cables. 3. A cable assembly according to claim 1 , further comprising a third coaxial cable disposed within the outer jacket, wherein only a shield of the third coaxial cable is enclosed within an inner insulator jacket to isolate the third coaxial cable from the first and second coaxial cables. 4. A cable assembly according to claim 1 , wherein the array is configured to:align the first and second coaxial cables and the drain wire to a corresponding ball grid array; and allow the first and second coaxial cables and the drain wire to be vertically connected to the ball grid array. 5. A cable assembly according to claim 1 , wherein the array is configured to:allow the first and second coaxial cables and the drain wire to be edge connected to a circuit board; and align the first and second coaxial cables and the drain wire to a corresponding position on the circuit board. 6. A cable assembly according to claim 1 , wherein a diameter of a dielectric of at least one of the first and second coaxial cables may be selected to alter a geometry of the array. 7. A cable assembly according to claim 1 , wherein a dielectric of at least one of the first and second coaxial cables may be selected to create a desired impedance of the corresponding coaxial cable. 8. A cable assembly according to claim 1 , wherein an outer diameter of the outer jacket is less than about six tenths of a millimeter. 9. A cable assembly according to claim 1 , wherein the first and second coaxial cables and the drain wire are not twisted along a length of the cable assembly. 10. A cable assembly according to claim 1 , further comprising:a third and a fourth coaxial cable disposed within the outer jacket, wherein:each coaxial cable comprises an exposed shield; the exposed shield of the third coaxial cable is in contact with the exposed shield of the fourth coaxial cable; and the exposed shields of the third and fourth coaxial cables are electrically isolated from the exposed shields of the first and second coaxial cables; and a second drain wire disposed within the outer jacket and in contact with the exposed shield of at least one of the third and fourth coaxial cables. 11. An internally shielded cable assembly for connecting to a source device having a connection layout including a ground connection, comprising:an outer jacket having an internal volume; a plurality of coaxial cables disposed within the internal volume of the outer jacket, wherein:each coaxial cable of the plurality of coaxial cables comprises an exposed outer shield extending along an entire length of the cable assembly; the exposed outer shield each coaxial cable of the plurality of coaxial cables is in contact with at least one outer shield of another cable of the plurality of coaxial cables; and a drain wire disposed within the internal volume of the outer jacket coextensively with the plurality of coaxial cables, wherein the drain wire is in contact with the exposed outer shield of at least one of the plurality of coaxial cables, and wherein: the plurality of coaxial cables and the drain wire are arranged in an array having an orientation configured to pre-align the plurality of coaxial cables and the drain wire to the connection layout of the source device to allow the drain wire to connect to the ground connection on the source device and act as a common ground for the plurality of coaxial cables. 12. An internally shielded cable assembly according to claim 11 , wherein the array is configured to:align the plurality of coaxial cables and the drain wire to a corresponding ball grid array; and allow the plurality of coaxial cables and the drain wire to be vertically connected to a corresponding solder ball connection point on the ball grid array. 13. An internally shielded cable assembly according to claim 11 , wherein the array is configured to:allow the plurality of coaxial cables and the drain wire to be edge connected to a circuit board; and align the plurality of coaxial cables and the drain wire to corresponding positions on the circuit board. 14. An internally shielded cable assembly according to claim 11 , wherein a diameter of a dielectric of at least one of the plurality of coaxial cables may be selected to alter a geometry of the array. 15. An internally shielded cable assembly according to claim 11 , wherein a dielectric of at least one of the plurality of coaxial cables may be selected to create a desired impedance of the corresponding coaxial cable. 16. A method of forming an internally shielded cable assembly for connecting to a source device having a connection layout including a ground connection, comprising: arranging a plurality of coaxial cables and a single drain wire in an array configured to pre-align the plurality of coaxial cables and the drain wire to the connection layout of the source device to allow the drain wire to connect to the ground connection on the source device, wherein: each coaxial cable comprises an exposed shield; the exposed shield of a first coaxial cable from the plurality is in contact with the exposed shield of a second coaxial cable from the plurality; and the drain wire is in contact with the exposed shield of at least one of the plurality of coaxial cables and acts as a common ground for the plurality of coaxial cables: and enclosing the plurality of coaxial cables and the drain wire within an outer jacket. 17. A method of forming an internally shielded cable assembly according to claim 16 , further comprising positioning an additional coaxial cable proximate the plurality of coaxial cables within the outer jacket, wherein only the additional coaxial cable is enclosed within an inner jacket and electrically insulated from the exposed shields of the plurality of coaxial cables. 18. A method of forming an internally shielded cable assembly according to claim 16 , further comprising positioning a second plurality of coaxial cables and a second drain wire within the outer jacket according to the connection layout of the source device, wherein:each coaxial cable from the second plurality of coaxial cables comprises an exposed shield; the exposed shield of a first coaxial cable from the second plurality is in contact with the exposed shield of a second coaxial cable from the second plurality; the second drain wire is in contact with the exposed shield of at least one coaxial cable from the second plurality of coaxial cables and connects to a second ground connection on the connection layout to act as a common ground for the second plurality of coaxial cables; and the second plurality of coaxial cables and the second drain wire are electrically insulated from the exposed shields of the first plurality of coaxial cables and the first drain wire. 19. A method of forming an internally shielded cable assembly according to claim 16 , wherein the array comprises a spacing between each coaxial cable and the single drain wire to allow the cables to be edge connected to a circuit board, wherein each wire is pre-aligned to a corresponding connection position on the circuit board. 20. A method of forming an internally shielded cable assembly according to claim 16 , wherein the array comprises a spacing between each coaxial cable and the single drain wire to allow the cables to be vertically connected to a ball grid array, wherein each wire is pre-aligned to a corresponding solder ball connection point on the ball grid array. 21. A method of forming an internally shielded cable assembly according to claim 16 , wherein a thickness of a dielectric of one or more coaxial cables from the plurality of coaxial cables may be selected to properly align the plurality of coaxial cables within the array.
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