Abstract:
The disclosed board fabrication techniques and design features enable the construction of a reliable, high-layer-count, and economical backplane for routers and the like that require a large number of signaling paths across the backplane at speeds of 2.5 Gbps or greater, as well as distribution of significant amounts of power to router components. The disclosed techniques and features allow relatively thick (e.g., three- or four-ounce copper) power distribution planes to be combined with large numbers of high-speed signaling layers in a common backplane. Using traditional techniques, such a construction would not be possible because of the number of layers required and the thickness of the power distribution layers. The disclosed embodiments use novel layer arrangements, material selection, processing techniques, and panel features to produce the desired high-speed layers and low-noise high-power distribution layers in a single mechanically stable board.
Abstract:
According to the invention, a microperforation (PMP) process step is combined with the lamination process. To this end, a dielectric layer (11,11') and a prefabricated product (1) are placed between two perforation dies (21,23) or a support and a perforation die. The prefabricated product (1) is partially covered by a conducting layer forming structures to be contacted by microvias. Pressure is applied on the perforation die (21,22), perforation tips of the perforation dies forming microvias for contacting the structures. A surface of the dielectric layer (11,11') or the prefabricated product (1) is configurated or coated to in a manner that the prefabricated product (1) and the dielectric layer (11,11') stick to each other after the pressure has been applied.
Abstract:
A system may include a first conductive ground pad, a second conductive ground pad, a first conductive via coupling the first ground pad to the second ground pad, a first conductive signal trace, a second conductive signal trace, and a second conductive via disposed within the first conductive via and coupling the first conductive signal trace to the second conductive signal trace. The first conductive ground pad and the second conductive ground pad may be disposed between the first conductive signal trace and the second conductive signal trace.
Abstract:
According to one embodiment, a broadband transition to joint a via structure and a planar transmission line in a multilayer substrate is formed as an intermediate connection between the signal via pad and the planar transmission line disposed at the same conductor layer. The transverse dimensions of the transition are equal to the via pad diameter at the one end and strip width at another end; The length of the transition can be equal to the characteristic dimensions of the clearance hole in the direction of the planar transmission line or defined as providing the minimal excess inductive reactance in time-domain according to numerical diagrams obtained by three-dimensional full-wave simulations.
Abstract:
A circuit board (200, 300, 400) design is disclosed that is useful in high speed differential signal applications uses either a via arrangement or a circuit trace exit structure. In the via arrangement, sets of differential signal pair vias (301, 303, 401, 402) and an associated ground (302) are arranged adjacent to each other in a repeating pattern. The differential signal vias (301, 303, 591) of each pair are spaced closer to their associated ground via (302a, 593a) than the spacing between the adjacent differential signal pair associated ground (302b, 593b) so that differential signal vias exhibit a preference for electrically coupling to their associated ground vias. The circuit trace exit structure involves the exit portions of the circuit traces (420, 550) of the differential signal vias (401, 402, 591) to follow a path where the traces then meet with and join to the transmission line portions (552) of the conductive traces.
Abstract:
A circuit board design is disclosed that is useful in high speed differential signal applications uses either a via arrangement or a circuit trace exit structure. In the via arrangement, sets of differential signal pair vias and an associated ground are arranged adjacent to each other in a repeating pattern. The differential signal vias of each pair are spaced closer to their associated ground via than the spacing between the adjacent differential signal pair associated ground so that differential signal vias exhibit a preference for electrically coupling to their associated ground vias. The circuit trace exit structure involves the exit portions of the circuit traces of the differential signal vias to follow a path where the traces then meet with and join to the transmission line portions of the conductive traces.
Abstract:
A high-speed router backplane, and method for its fabrication, are disclosed. The backplane uses differential signaling trace pairs on multiple high-speed signaling layers, the high-speed signaling layers separated by ground planes. Plated signaling thru-holes connect the trace pairs to the board surface for connection to external components. The signaling thru-holes pass through clearances in each ground plane. At selected ground planes, a conductive pad is patterned within each high-speed signaling thru-hole clearance, the pad slightly larger than the thru-hole diameter. The pads affect the impedance characteristics of the thru-holes, thus providing a better impedance match to the differential trace pairs, reducing signal reflections, and improving the ability to signal across the backplane at high speeds.
Abstract:
A high-speed, high-power modular router is disclosed. As opposed to conventional designs using optical backplane signaling and/or bus bars for power distribution, the disclosed embodiments combine high-power, low-noise power distribution with high-speed signal routing in a common backplane. Disclosed backplane features allow backplane signaling at 2.5 Gbps or greater on electrical differential pairs distributed on multiple high-speed signaling layers. Relatively thick power distribution layers are embedded within the backplane, shielded from the high-speed signaling layers by digital ground layers and other shielding features. A router using such a backplane provides a level of performance and economy that is believed to be unattainable by the prior art.