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LayoutGen - Preparing the AutoCAD layout for Import to APD


The LayoutGen module runs inside of AutoCAD and takes a user step-by-step through the procedures necessary to organize a package layout so that it contains all the intelligence needed to import into APD/SIP.

The net result is a ULF (universal layout format) file that contains all of the necessary intelligent elements that APD requires for creating a database.


leadframe w die and wires

Lead frame drawn in AutoCAD with Die and Wires

Step by Step

LayoutGen takes you through the various steps needed to produce an intelligent database

New Project - defines the units and the layer cross section (needed by APD)

Line Linker - links geometries drawn with lines and arcs into closed figures.

Poly Reversal - clips and reverses lead frames that were drawn in reverse polarity.

Shape Builder - converts zero width closed polylines into shapes and supports voids.

Pin Builder - generates a pin at the end of each lead frame lead

Symbol Builder - creates the die symbol by scanning and package symbol

Wire Builder - identifies wires and determines to which die pad they are attached.

Wing Via - generates a via from the lead frame layer to the "bottom" which simulates the gull wing

Gull Wing Via - a more advanced and accurate model of the gull wing lead.

Net Builder - traces the connections between die pads, wires, shapes and package pads.

Export Layout - exports the results to the ULF database.

The LayoutGen Menu


In addition to the above functions, LayoutGen includes several utilities which are accessed from the Utilities... menu pick.

Layoutgen Utility Menu Items

Symbol Copy/Place

Some multi-chip designs use the same die and place it 2 or 3 or even 4 times. Copy symbol allows you to build the die symbol once, and then place additional copies of it as needed.

dialog for copying a symbol


1) Although the symbol names in principle are the same you cannot assign them the same name; this is not a function that LayoutGen supports.

2) The transformation is relative to the coordinates of the source symbol - not to 0,0.

Converting Layout Created using AIF

If you are working with a wirebond document that created the die symbol by importing an AIF file then this utility will automatically generate the die symbol for you. You only have to specify the layer that the die pads are placed on and the layer for the die outline. The die pad numbers and nets will be read from the block attributes on the die pads.

dialog for converting AIF generated layout into a LayoutGen symbol

Viewing Net Connections

After net building you may wish to review elements to determine the nets that were correctly built. You can use this utility to click on the list of nets and see highlighted on the screen all elements of that net or you can click on a element on screen and see what net it belongs to.

net viewer can highlight all elements belonging to a net

The net viewer can be either driven from the net list names or from the display.

Xdata Viewer

This utility shows any extended data that has been created and attached to an AutoCAD entity by the LayoutGen program. There are different categories of extended data: object defines an entities object type, net defined an entity's net, parent defines a entities parent (for shapes), and so on. These hold the "intelligence" needed to create a valid APD database.

Xdata viewer shows an elements Xdata attached to it

In this example the entity selected was a shape on layer (APD subclass) TOP_COND. It connects to entities with handles 1F01 and 16C8 and it belongs to net 20.

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