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Method for signal net details report automation using component traversal

IP.com Disclosure Number: IPCOM000006264D
Publication Date: 2001-Dec-19
Document File: 7 page(s) / 1K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for signal net details report automation using component traversal. Benefits include improved consistency and reliability of results and decreased processing time.

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Method for signal net details report automation using component traversal

Disclosed is a method for signal net details report automation using component traversal. Benefits include improved consistency and reliability of results and decreased processing time. 

General description

      The disclosed method uses software to accumulate signal net details within a CAD design tool. The purpose is to address electromechanical interference (EMI) concerns that may arise from the poor planning of vias and components along certain nets.

The key elements are:

·        CAD Viewer for the CAD design (package/board/interposer)

·        Uses native CAD database (no conversion or translation of design data required)

              Designers and engineers of printed circuit board and packages sometimes require signal net details when checking their design for EMI issues. These details may include counts of the following items:

·        Component pins associated with each signal net

·        Vias associated (vertical connections)

·        Tees (forks in trace routing)

·        Points the net traverses though

              CAD tools recognize a net as a new logical net when the trace passes through a component such as a 0-ohm (0 Ω) resistor. However, a designer’s viewpoint is that the nets on either side of this type of component, although connected in series, are virtually the same net. Therefore, the details of the net should include both nets and other series components that are recursively connected to the initial net.

              The conventional method for making this type of determination is a manual process. While software may exist for accumulating an entity list per logical net, no software handles separate nets connected through a given component as one virtual net on which to tally relevant entities. The designer or engineer must either count relevant entities from within the CAD environment, following the net through junctions and stack layers to the best of the individual’s ability, or do the same from a printout of the design. When automation exists per net, the user must determine which group of nets to run the automation on (the accumulation of all logical nets that make up the virtual net), run the automation for each, and manipulate the results.

Detailed description

              The Signal Net Details automation runs from within a CAD tool environment. The automation program has the capability to query the design database for information, report to the user using markers added to the database, and generate an output report.

              The software uses the algorithm depicted in Figure 1. The automation first determines the components that should be traversed through. It identifies a predefined set of components that includes 0-ohm resistors (according to the conventional automation). The signal nets that are to be queried are also identified using predefined criteria. A list of nets is built based upon all the nets that are interrelated through the traversed components. All the pins on the signal nets are analyzed to determine if they are also pins on a...