Abstract:
A distributed transmission line structure (10) includes a ground plane (26) affixed to a substrate (12). The substrate (12) is formed of a generally nonconductive material. A first metallic strip (14) is affixed to the substrate (12) and is electrically connected to the ground plane (26) through a first through-hole (34). A second metallic strip (16) is affixed to the substrate (12) and is spaced apart from the first metallic strip (14) by a gap (28) and is electrically connected to the ground plane (26) through a second through-hole (38). A dielectric layer (20) overlies the substrate (12), the first metallic strip (14), and the second metallic strip (16). A third metallic strip (18) is affixed to the dielectric layer (20) and is disposed to overlie the gap (28). The third metallic strip (18) has a width less than the gap (28). The impedance of the distributed transmission line structure (10) is substantially constant over a predetermined range of thickness of the dielectric layer (20).
Abstract:
A power distribution system for a multi-layer circuit board includes a board having a component layer with signal runs formed thereon, a ground layer, an insulation layer, and a power supply system. The power supply system includes a supply bus, discrete voltage supply planes, and isolation devices mounted on the component layer, each connecting one of the discrete voltage supply planes to the supply bus. The component layer has a first area for components which perform a first function and a second area for components which perform a second function. The discrete voltage supply planes include a first supply plane corresponding to the first area and a second supply plane corresponding to the second area. The first supply plane is disposed directly beneath and is shaped substantially the same as the first area, and the second supply plane is disposed directly beneath and is shaped substantially the same as the second area. The first supply plane, the second supply plane, and the supply bus lie in a plane between the insulation layer and the component layer.
Abstract:
The invention features a method for flowing solder in a gap between two surfaces. A supply of solder is heated to cause it to reflow and flow in the gap. The solder is directed to flow as a main stream in the gap and to flow as peripheral streams from the main stream toward edges of the gap to reduce formation of voids.
Abstract:
A cable (1) on an end of an electrical cable, is constructed with, a flexible and flat conductive shield (7), a flexible ribbon of insulation (3) separating the shield (7) from multiple flexible signal conductors (2) extending along the insulation (3), and at least one flexible ground conductor (6) between the insulation (3) and the shield (7), the signal conductors (2) are spaced apart on pitch spacings, with a signal conductor (2) being absent from at least one of the pitch spacings, and the ground conductor (6) extending above said one of the pitch spacings.
Abstract:
An electrical connection system, for example a dropside patch panel, comprises a mounting rail (12) which receives first connectors (14) arranged with their contacts facing away from the rail (12). Cable introduced between the rail and the connectors is separated into individual conductors which are terminated at contacts (34, 36) via slots (30) in the rail walls. A second connector (16) carries standard data or voice sockets communications (19) which are connected to the first connector via edge contact carrying PCBs (38) which engage in slots (40) in the first connectors. The PCB edge connectors have a discontinuity on one surface, and one half of the contact is connected to the contact on the other side of the PCB to provide a jumpered interconnection between upper (34) and lower (36) rows of contacts of the first connectors in a first position of the second connectors, and contact between the upper rows of contacts and the standard sockets (19) when the second connectors are moved further into the slots (40) to occupy a second position. The slots (40) are formed to receive the PCBs (38) from either end.
Abstract:
A printed wiring pattern for preventing poorly soldered connection that tends to occur when soldering surface mounting chip components and lead terminals of mounting components on the printed wiring pattern is capable of making the detection of a poorly soldered site a simple task.
Abstract:
An electronic component (14) is soldered to a circuit carrying substrate (11) by a method that allows the component to remain in better contact with the flat solder pads of the substrate. The circuit carrying substrate (11) has a plurality of solder pads (12) disposed thereon, each pad consisting of a terminal portion (16), a solder reservoir portion (18), and a bridging portion (17). The terminal portion is connected to the reservoir portion by the bridging portion. The bridging portion is typically a necked down portion of the pad. The electronic component (14) has a plurality of solderable terminals (15) corresponding to the terminal portions (16) of the solder pads (12). Each of the solder pad reservoir portions are coated with a reservoir of solder (23). The amount of solder coated onto the reservoir portion is sufficient to provide a fillet between the component (14) and the solder pad terminal portion (16) during a subsequent heating step. A flux (25) is then applied to the solder pad terminal portions (16), and the electronic component (14) is placed on the circuit carrying substrate so that each of component terminals is in the flux and contacts the terminal portions of the solder pads. The entire assembly is then heated to melt the solder, thereby causing the melted solder to flow across the solder pad bridging portion and form a fillet between the solder pad terminal portion and the component terminal.
Abstract:
In method for electrically connecting sections of a split plane in a printed circuit board, conductive strips are placed on a surface plane of the printed circuit board, along borders of the sections of the split plane. The conductive strips are connected to the sections of the split plane through vias. For every first section and second section which are to be electrically connected, a single piece of conductive material is connected to a conductive strip placed on a border of the first section and is connected to a conductive strip placed on a border of the second section. Testing may then be performed to determine electromagnetic properties of the printed circuit board for different combinations of the sections being connected together. From the results of the testing the optimal borders for the split plane can be determined.
Abstract:
An SMT electronic component is mounted to a solder-bearing floatation plate by fusible or other heat-responsive releasable mounting means which suspend the component above the floatation plate. The bottom of the floatation plate is effectively substantially the mirror image of a component-positioning pad formed on the board surface adjacent the solder-bearing contact pads corresponding to the electrical contacts on the component. In the assembly process, the floatation plate is placed on the positioning pad. The solder on the bottom of the floatation plate has a melting point lower than the release temperature of the mounting means and the melting point of the solder on the contact pads. With the floatation plate on the component-positioning pad, on heating the solder on the floatation plate liquifies first, wetting the component-positioning pad and floating the floatation plate and component on a thin film of molten solder. Surface tension forces bring the floatation plate into registry with the component-positioning pad. On further heating, the solder on the contact pads liquifies, and the heat-responsive mounting means allows the component to fall freely onto the contact pads. Guide means are provided to prevent rotational and lateral displacement of the component during the fall. The disclosure includes alternative floatation plate constructions and component mounting arrangements.
Abstract:
Electromagnetic filtering for a VLSI device having multiple power input leads is realized by employing a sub-power plane which is physically separate from a main power distribution system on a circuit board. The sub-power plane is placed directly under a corresponding VLSI device. Decoupling capacitors are connected to the sub-power plane and, in turn, to each of the power input leads on the VLSI device. Power is supplied from the main power distribution system to the sub-power plane via a ferrite bead type filter.