Abstract:
Plated through holes pass through clearances in a ground plane of a circuit board. A conductive collar/spoke arrangement is constructed on the ground plane adjacent the clearance, to provide an inductive component to the coupling between a plated through hole and the ground plane. The inductive component impedes the transfer of high-frequency noise between the through hole and the ground plane. Other embodiments are also described and claimed.
Abstract:
Substrates having power and ground planes, such as, for example, printed circuit boards, include at least one noise suppression structure configured to suppress electrical waves propagating through at least one of a power plane and a ground plane. The at least one noise suppression structure may include a power plane extension that extends from the power plane generally toward the ground plane, and a ground plane extension that extends from the ground plane generally toward the power plane. The ground plane extension may be separated from the power plane extension by a distance that is less than the distance separating the power and ground planes. Electronic device assemblies and systems include such substrates. Methods for suppressing noise in at least one of a power plane and a ground plane include providing such noise suppression structures between power and ground planes.
Abstract:
A filter for filtering noise generated by a differential signal having a specific wavelength transmitted by a first transmission line and a second transmission line is disclosed. The filter includes a multi-layer substrate, a first microstrip line and a second microstrip line. The first and the second transmission lines and the first and the second microstrip lines are disposed at the multi-layer substrate. In addition, one end of the first microstrip line and one end of the second microstrip line are electrically connected to the first and the second transmission lines, respectively, by passing through the vias, and the other end is in a floating state. The impedances of the first and the second microstrip lines match the impedances of the first and the second transmission lines, respectively. Thus, the first and the second microstrip lines may filter the noise generated by the differential signal having the specific wavelength.
Abstract:
A differential signal via structure for a printed circuit board having a pair of signal vias extending vertically from a surface of the board to an interior region of the board to contact signal conductors disposed horizontally within the interior region of the board and a pair of ground vias extending vertically from a surface of the circuit board to an interior region of the board to contact ground conductors disposed horizontally within the interior region of the board.
Abstract:
A wiring board equipped with differential lines which compensate for differences in via lengths to minimize signal deterioration is disclosed. Two conductors are couple to different substrate levels through vias of different lengths. Compensation means are provided to correct for the phase difference caused by the different lengths.
Abstract:
An integrated circuit package having a multi-segment transmission line transformer for impedance matching a packaged integrated circuit, such as a driver or receiver, to a printed circuit board (PCB) transmission line to which the packaged chip is attached by, for example, solder balls. In one exemplary embodiment, a three-segment transmission line transformer provides improved broadband performance with the advantage of having a middle segment with a flexible length for easier routing. The length of each end segment of the three-segment transformer is adjusted to provide at least partial cancellation of reflections between the PCB and the transformer, and between the transformer and a circuit on the integrated circuit, respectively. Further, the inductive reactance of the solder balls and via wiring may be cancelled out by the transformed chip impedance to provide a non-inductive termination to the PCB transmission line at approximately one-half the highest data rate of the channel.
Abstract:
A high-speed router backplane is disclosed. The router backplane uses differential signal pairs on multiple signal layers, each sandwiched between a pair of digital ground layers. To reduce routing complexity, at least some of the differential signal pairs route through a via pair, somewhere along their path, to a different signal layer. Specific via designs reduce differential signal distortion due to the via pair, allowing the backplane to operate reliably at differential signal rates in excess of 3 Gigabits per second. In particular, each via passes through nonfunctional conductive pads on selected digital ground plane layers, the pads separated from the remainder of its ground plane layer by a clearance, thereby modifying the impedance of the via and reducing reflections from the stubs created by the via.
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:
Printed circuit board in which deterioration of signal transmission characteristics otherwise caused by a stub parasitically formed in a through-hole is suppressed to provide optimum high-speed signal transmission characteristics. A printed circuit board 10 includes a power supply/ground layer 11 and a signal line 12b in a dielectric layer 13, and a through-hole 12 connected to the signal line 12b. A clearance 14 which becomes an anti-pad is provided in an area between the through-hole 12 and the power supply/ground layer 11. The signal line 12b is extended from the through-hole 12 through the clearance 14 to an area below the power supply/ground layer 11. The portion of the signal line 12b arranged in the vicinity of the power supply/ground layer 11 in the clearance 14 has an area of impedance gradient 17 whose characteristic impedance becomes progressively lower in a direction away from the through-hole 12.
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.