Abstract: An exemplary FPCB includes a signal layer having a differential pair consisting of two transmission lines arranged therein, a ground layer, and a dielectric layer lying between the signal layer and the ground layer. Two sheets made of conductive materials are respectively arranged at opposite sides of the differential pair, and both connected to ground. The sheets are apart from and parallel to the transmission lines. The ground layer has a void defined therein, and the void is located under the two transmission lines.

Abstract: A printed circuit board (200) includes at least one via (280) defined therein, the via has an upper cap (220) formed on a top surface of the PCB, and a lower cap (240) formed on a bottom surface of the PCB. A conductive hole (290) is defined in the PCB having a plated sidewall (230) plated on its inner surface, and a first clearance hole (271) is defined in a first inner layer (260) of the PCB around the sidewall. A first transmission line (210) defined on the top surface of the PCB is coupled to the upper cap, a first void (273) extending from a boundary of the first clearance hole being disposed along the layout direction of the first transmission line.

Abstract: A printed circuit board includes a first signal layer, a second signal layer, a plurality of transmission lines respectively including first segments laid in parallel on the first signal layer and second segments laid in parallel on the second signal layer, and a plurality of vias, each via connecting the first segment with the second segment of a corresponding transmission line. One of the plurality of transmission lines has the first segment positioned in the middle of an array defined by the first segments of the plurality of transmission lines, and a second segment positioned in an outmost position of an array defined by the second segments of the plurality of transmission lines. The printed circuit board reduces the possibility of false action of electronic components coupled to transmission lines, which is caused by the crosstalk between transmission lines.

Abstract: An exemplary printed circuit board includes at least a pair of differential vias defined therein, each of the differential vias has an annular ring formed on the PCB, a conductive hole defined in the PCB, and a clearance hole defined in at least one inner layer of the PCB. Each of the clearance holes of the differential vias is oval shaped thus providing a greater area for the clearance holes and needed clearance between vias without creating a superposition zone.

Abstract: A printed circuit board (PCB) includes at least one power trace. A plurality of etched portions are defined in the at least one power trace, acting as electromagnetic bandgaps for transferring resonant frequencies produced around the at least one power trace to avoid working frequencies of the PCB, thereby reducing power noise around the at least one power trace.

Abstract: An exemplary circuit board includes a power plane with a first metal plate, a ground plane with a second metal plate, a channel etched in one of the metal plates to define an isolated area therein, and a coupling circuit. A gap is formed between the isolated area and other area of the one of the metal plates. The coupling circuit is electronically connected between the first and the second metal plates in the isolated area for reducing a resonance frequency caused by the channel. The circuit board can reduce electromagnetic interference generated therein.

Abstract: A method for reformatting a motherboard design file includes the steps of: converting the motherboard design file from a first format to a second format, and generating a converted temp file based on the motherboard design file; selecting information classes of the converted temp file; parsing contents from the converted temp file according to the information classes; data checking thickness of each layer according to thickness information of each layer; data checking circuit configuration of the motherboard according to information of pads and etching information of circuits; and encoding needed codes according to thickness of each layer and circuit configuration of the multilayer motherboard, and generating the motherboard design file based on the needed codes. A system for reformatting a motherboard design file is also disclosed.

Abstract: A signal transmission line used in a printed circuit board (PCB), the signal transmission line comprises a driving terminal for driving a signal, a contact portion, the signal line connected with the driving terminal and the contact portion to transmit the signal wherein a length of the signal line is so arranged that a time for the signal transmitted from the driving terminal to the contact portion is not less than half of a time for the transmitted signal to reach a receiving terminal.

Abstract: A multilayer printed circuit board (PCB) includes a plurality of signal planes, two reference planes, a signal via, and a stitching via. The signal via passes through all planes for a signal trace flowing therethrough. The stitching via is defined near the signal via and electrically connects to one of the reference plane. The stitching via serves as a stitching capacitor, to reduce the area of the signal current flows in the PCB, even to control crosstalk and lower the noise on the PCB. It is of advantage that the stitching via is simple to manufacture and very suitable for mass production.

Abstract: A two-layer printed circuit board (PCB) having impedance control is provided. The two-layer PCB includes: a substrate; a plurality of transmission lines laid on the substrate for transmitting high-speed signals, each of the transmission lines having a standard impedance; and at least one ground trace laid on the substrate adjacent each of the transmission lines, for controlling a characteristic impedance of each of the transmission lines to equal or approach the standard impedance.