Force10 Networks, Inc.

Dell Products Inc.

Forcelo Networks, Inc.

Greg Hunt

Joel R Goergen

Joseph Pankow

Michael Laudon

Peter Tomaszewski

Ashby Armistead

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. Thru-holes are used to connect the differential signal pairs to external components. 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. At least some of the thru-holes and vias are drilled to reduce an electrically conductive stub length portion of the hole. The drilled portion of a hole includes a transition from a first profile to a second profile to reduce radio frequency reflections from the end of the drilled hole.

Method of fabricating a circuit board

The characteristic impedance of a surface pad is manipulated by reticulating the pad and filling the spaces with a dielectric material, providing an inductive element in the coupling of the surface pad to an underlying ground pad of a ground plane, or a combination of these approaches. In appropriate embodiments, acceptable signal trace routing paths will exist in an embedded signal layer under the ground plane and crossing under the surface pad. Other embodiments are also described and claimed.

High-speed router with backplane using muli-diameter drilled thru-holes and vias

Impedance tuning for circuit board signal path surface pad structures

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.

Inductance-tuned circuit board via crosstalk structures

A high-speed router backplane is disclosed. The disclosed construction and layout techniques enable the construction of a reliable, high-layer-count, and economical backplane for routers and the like that use signaling across the backplane at trace speeds of 2.5 Gbps or greater. Specific ranges of differential trace geometry characteristics, with significant single-ended coupling to adjacent ground planes, have been found to provide the parameters needed for such signaling. New trace routing and layering techniques also help in the realization of a backplane embodiment containing roughly 600 operable high-speed differential pairs, while also providing sufficient electromagnetic interference management to allow power distribution to occur within the same backplane.

Growing community of inventors

San Jose, CA, United States of America

Greg Hunt