Abstract:
A method of manufacturing a multilayered circuit board includes the steps of: manufacturing a laminated body by laminating a prepreg of a predetermined thickness on at least one surface of a double-sided circuit board having a grounding link and a signal wiring patterned on both surfaces thereof; and applying heat and pressure to the laminated body and completing a layered structure in which the signal wiring is laid inside the prepreg at a boundary between the double-sided circuit board and the prepreg, wherein prepreg sheets of a predetermined thickness are used in a completed layered structure so that a thickness of a prepreg of the double-sided circuit board is smaller than a distance between a surface of the prepreg on a side not opposed to the double-sided circuit board and the signal wiring laid inside the prepreg.
Abstract:
A multi-layer circuit board includes first, second, third, fourth, fifth, sixth and seventh insulating substrates; first, second, third, fourth and fifth signal wiring layers; first and second ground wiring layers; and a power wiring layer. Each of the first and seventh insulating substrates has a thickness ranging from 2.5 to 6.5 mil. Each of the second, fourth and sixth insulating substrates has a thickness ranging from 3 to 9 mil. Each of the third and fifth insulating substrates has a thickness ranging from 3 to 23 mil. The first signal wiring layer has a first resistance with respect to the first ground wiring layer. The second signal wiring layer has a second resistance with respect to the first ground wiring layer and the power wiring layer. The third signal wiring layer has a third resistance with respect to the first ground wiring layer and the power wiring layer. The fourth signal wiring layer has a fourth resistance with respect to the second ground wiring layer and the power wiring layer. The fifth signal wiring layer has a fifth resistance with respect to the second ground wiring layer. The first, second, third, fourth and fifth resistances are within the range of 49.5 to 60.5 ohms.
Abstract:
Method and apparatus are disclosed for flow control over Point-to-Point Protocol (PPP) data links. A method of negotiating such flow control between two PPP peers is disclosed, along with methods for operating flow control across a PPP link. In one embodiment, flow control frames carry an IEEE802.3x MAC control frame payload—the PPP implementation repackages such frames as MAC control frames and passes them to a MAC, which performs flow control. In another embodiment, flow control frames allow flow control commands to be applied differently to different service classes such that PPP flow can be controlled on a per-class basis.
Abstract:
A backplane assembly includes a main backplane having a first power conductor, a backplane strip having a second power conductor, and connecting members disposed between the main backplane and the backplane strip. The connecting members hold the backplane strip in a fixed position relative to the main backplane and electrically connect the first power conductor and the second power conductor. In one arrangement, the connecting members include source standoffs which extend from a source area of the main backplane to the backplane strip, and target standoffs which extend from a target area of the main backplane to the backplane strip. The source and target standoffs and the second power conductor provide a current path which increases current carrying capacity from the source area to the target area above that provided by the first power conductor alone. Thus, the backplane assembly is well-provisioned for distributing high currents to circuit boards.
Abstract:
A multi-layer module for packaging an electronic component comprises an uppermost electrically conductive layer for mounting the component, a plurality of electrically insulative layers, and a plurality of electrically conductive layers disposed between the insulative layers. The electrically conductive layers form staggered placements of at least three voltage and/or ground distribution layers close to the module surface without signal wiring layers in between, and signal distribution layers comprising signal conductors. Vias form conductive paths through the insulative layers and conductive layers; the corresponding signal, voltage and ground distribution layers are electrically connected with each other and with the uppermost layer.
Abstract:
The present invention is a reconfigurable substrate which includes at least one signal line layer stack. Each signal line layer stack is defined to include two substantially parallel insulating layers and a signal line layer interposed between the two insulating layers and substantially parallel to the insulating layers. The substrate includes at least one conductive isolation layer adjacent to at least one signal line layer stack and substantially parallel to the at least one signal line layer stack. The substrate is reconfigurable to different performance levels by adding or removing at least one conductive isolation layer.
Abstract:
A multi-layer circuit board includes first, second, third, fourth and fifth insulating substrates, first, second, third and fourth wiring layers, a ground wiring layer and a power wiring layer. The insulating substrates and the wiring layers are press-bonded to each other to form the circuit board with a thickness of about 1.6 mm. Each of the first and fifth insulating substrates has a thickness of 5.7±0.285 mil. Each of the second and fourth insulating substrates has a thickness of 8±0.4 mil. The third insulating substrate has a thickness of 24.6±1.23 mil. The first signal wiring layer has a first resistance with respect to the ground wiring layer. The second signal wiring layer has a second resistance with respect to the ground wiring layer and the power wiring layer. The third signal wiring layer has a third resistance with respect to the ground wiring layer and the power wiring layer. The fourth signal wiring layer has a fourth resistance with respect to the power wiring layer. The first, second, third and fourth resistances are within the range of 49.5 to 60.5 ohms.
Abstract:
A printed circuit board having multiple layers, includes: a copper film for removing signal interference and noise and matching impedance, formed between pads of a lowermost layer which are connected to of an uppermost layer.
Abstract:
In a multi-layer printed-wiring board (100) the ground and power conductor-bearing layers (102 and 103) are placed immediately (without intermediancy of other conductive layers) below the outer surface conductor-bearing layers (101) and are connected to the outer surface layers by micro-vias (110 and 111) that do not extend beyond the ground and power layers, whereby the micro-vias avoid causing trace-routing blockages on lower, signal-routing, layers (104). The surface layers define traces for static and infrequently-changing signals. One or both of the ground and power layers define double pads (203) each comprising a pair of normal pads (204-205) interconnected by a short trace (206). One single pad of each pair is connected by a micro-via to a corresponding pad (202) on an outer surface layer, which also typically has a lead (201) of a component (200) soldered thereto or serves as a testpad. The other single pad of each pair is connected by a buried through-hole via (207) to pads (208) on the lower, signal-routing, layers. This removes the double pads from the outer surface layer and thus reduces trace-routing blockages on the outer surface layer, and at the same time solves the problem of connecting micro-vias to through-hole vias.