Cisco Technology, Inc.

Yaochao Yang

Joel Richard Goergen

Amendra Koul

Mike Sapozhnikov

Kartheek Nalla

Soumya De

Hui Wu

A method is provided that includes inspecting a layer of a printed circuit board through an inspection window comprising an opening formed in one or more other layers of the printed circuit board and identifying a location of a trace aligned with the inspection window, relative to a marker in a fiber bundle of a fiber weave to assess fiber weave skew.

Fiber weave skew assessment for printed circuit boards

In one embodiment, a method includes inspecting a fiber weave for use in a printed circuit board with an automated optical inspection tool and identifying a distance between fiber bundles in the fiber weave. The fiber weave comprises a plurality of the fiber bundles woven to form the fiber weave and a portion of the fiber bundles comprise markers and identifying a distance between the fiber bundles in the fiber weave comprises measuring a distance between the markers.

In one embodiment, a method includes inspecting a layer of a printed circuit board through an inspection window comprising an opening formed in one or more other layers of the printed circuit board and identifying a location of a trace aligned with the inspection window, relative to a marker in a fiber bundle of a fiber weave to assess fiber weave skew.

In one embodiment, a method generally comprises importing a layout identifying routing information for a plurality of differential pair traces on a printed circuit board at a skew assessment module, receiving values for a plurality of skew parameters associated with fiber weave skew, receiving variation parameters from a database comprising data collected on fiber weave variation for one or more of the skew parameters, calculating a skew estimate for the printed circuit board based on the skew parameters and the variation parameters at the skew assessment module, and determining if the skew estimate is within a specified skew allowance for the printed circuit board.

Techniques are disclosed to determine the temperature-dependent insertion loss and propagation delay of traces in a printed circuit board design. For example, an example method includes determining a first temperature at a first portion of a trace of a PCB design based on a thermal map of the PCB design. The method further includes determining a second temperature at a second portion of the trace based on the thermal map. The method further includes calculating a temperature-dependent property of the PCB at the first portion based on the first temperature. The method further includes calculating the temperature-dependent property of the PCB at the second portion based on the second temperature. The method further includes calculating at least one of a signal loss and propagation delay on the trace based on the temperature-dependent property of the PCB at the first portion and the second portion.

Temperature-dependent printed circuit board trace analyzer

In one embodiment, an apparatus includes a contact contained within a connector configured to couple with a mating connection to provide a communications data path through the connector, a ground shroud extending over a portion of the contact, and a self-terminating element connected to one of the contact and the ground shroud and configured for engagement with the other of the contact and the ground shroud when in an engaged position with the connector uncoupled from the mating connection to terminate signals transmitted to the connector, and disengagement when in a disengaged position with the connector coupled with the mating connection.

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Fremont, CA, United States of America

Yaochao Yang