Exporting IFF Layout Files from ADS

This chapter describes the procedure for exporting an Advanced Design System design, including layout and schematic, to Intermediate File Format (IFF).

IFF Layout and Schematic Export from ADS

The basic procedure for exporting a design from ADS can be broken down into several simple steps:

Opening an ADS Project and Layout Window
Accessing the MGC/PCB Export dialog
Selecting MGC/PCB Export Options
Completing the MGC/PCB Export

Exporting an IFF Layout File

This section describes the procedure for exporting an IFF layout file from Advanced Design System using the MGC/PCB Translator's User Interface. Before exporting an IFF layout file, refer to Opening an ADS Project and Layout Window.

Accessing the MGC/PCB Export dialog

To access the PCB/MGC export dialog, launch your export from an ADS Layout window.

Open your ADS Layout Design in the ADS Layout window.
Choose File > Export. The schematic Export dialog box appears. Select MGC/PCB for the File Type.
Note
It is recommended that the MGC/PCB export option be used in favor of the IFF option when transferring layouts to Mentor Graphics.

Where do the files go?

When exporting schematic data to IFF files, you are able to choose the destination file name. The MGC/PCB Export does not allow you to specify where to save the data. The MGC/PCB export is actually exporting both the schematic data and the layout data simultaneously. Mentor Graphics Boardstation, in order to do packaging and layout, requires that there be a schematic associated with a layout. It is actually impossible to import the layout data alone into Mentor Graphics - you must import both schematic and layout data simultaneously.

Because both files are needed to do a successful import, the MGC/PCB export hard codes the file names, so that they will be easily identified when you later choose to import them into Mentor. In the project containing your design, a new directory, to_mgc, will be created. Within that directory, a directory will be created, called <design name> .hpxfer. Within that directory, there will be three files:

design_info - contains optional user comments.
layout.iff - contains the layout representation of the design.
schematic.iff - contains the schematic representation of the design.
For example, if a design was created called demo, in the project directory, a new directory would be created called to_mgc . Within to_mgc, there would be a directory called demo.hpxfer . Within demo.hpxfer, there would be a file called design_info , a file called layout.iff , and a file called schematic.iff .

Selecting MGC/PCB Export Options

This section describes the choices available in the schematic MGC/PCB Export Options dialog box.
To access the MGC/PCB Export IFF Options dialog box from the Export dialog

Click More Options . The MGC/PCB Export IFF Options dialog box appears.
In the MGC/PCB Export Options dialog box, select the appropriate options for your translation using the information below.

IFF File Overwrite Options

Overwrite IFF File - When writing to an existing file, the contents of that file are overwritten. This is the default setting, and, for MGC/PCB export, you should always use this setting.

Append to IFF File - When writing to an existing file, the new file is appended to the existing file. The IFF file is not overwritten during the ADS export by default. To transfer multiple designs, simply use the same file multiple times. Each design is created in turn. This method enables you to transfer a limited amount of hierarchy when you don't want to overwrite reference elements. To implement this method, set the hierarchy level to None , then export one sub-network followed by the main design. No IFF data is generated for any of the referenced components in either design, so the only two circuits overwritten during an import are the two designs transferred.

Output disabled instances to the IFF file

When this option is selected, if an instance is disabled in the schematic, it will still be output into the IFF file. If the checkbox is deselected (default), disabled instances will not be exported. This option can be utilized to omit certain components from being transferred to remote environments that might not support the components (e.g. disable the simulation components prior to creating an IFF file to send to Mentor Graphics, which does not have any definitions for the simulator components). Activate this option if you want to get everything. Deactivate this option if you want to filter out the unused/unwanted components.

Output ADS Item Definition properties

When this option is selected, ADS Item Definition properties are utilized to recreate the information necessary to simulate a component for ADS. For example, if you have parameters on a resistor, some Item Definition properties are created in the IFF file (e.g. R_ADS_UNIT=1), which allow the IFF importer to exactly recreate the component as it exists in ADS. However, other tools will not recognize the Item Definition parameters, and may misinterpret the properties as being separate. If library symbols are being exported to other environments that do not recognize the ADS Item Definition parameters, the option should be turned off. This option is deselected by default.

Put a space between numbers and the scalar/unit

When this option is selected, parameter values are exported as they normally appear in ADS (i.e. with a space between the number and the scalar, e.g. "1 pF"). If the checkbox is deactivated, the exporter converts the values into the IFF value specification, which is to have no space between a number and a scalar (e.g., "1pF"). Ideally, an IFF exporter should interpret either form of number, and set the value internally to whatever is normal for that environment. Mentor Graphics does not interpret the IFF property values in any way, and expects that the values from ADS will have a space in them. The RF Architect ADS library is set up to expect values to have a space between a number and a scalar/unit. If the space is not there, the ADS components (e.g. MLIN) will not be placed properly. For an MGC/PCB transfer, this option should always be selected. This option is deselected by default.

Default Library Name for Library Parts

When the IFF file does not specify a library name for a component that needs to be created, the library name specified in this field is used. This is necessary for environments that do not support the concept of a library.
Design objects are stored in a group that uses the same name as the project directory, but library parts are stored in either the default library hpeesoflib or a library that you specify. The default library name can contain only alpha numeric characters.

Note
The Default Library Name For Library Parts field is identical to the field of the same name in the Import IFF Options dialog box. Changes made to this field will modify the contents of the field in the Import IFF Options dialog box.

About Component Libraries

A component library in ADS consists of a collection of component definitions. Each primitive component has an associated component name, symbol and predefined component parameters that include relevant physical and electrical characteristics.

The IFF Translator can be used as the initial step in creating an ADS component library however, this topic is outside of the scope of this manual. Creating an ADS component library using IFF requires specialized tools and training. If you're interested in learning more about this topic, contact Agilent EEsof-EDA's Solution Services.

Schematic Hierarchy Option

The Schematic Hierarchy Option drop-down list enables you to establish how much of the design hierarchy is exported:

Current Design Only Write current level only. Complete design information for the current design is exported. Instance-specific information (parameter values and coordinates identifying position) is also exported. Detailed definitions of a referenced design are not exported.

Current Design, Selected Projects and No Library Parts Complete design information for the current design is exported. Referenced designs that reside in a project selected for inclusion during export and are part of the current design's hierarchy are also exported. Library parts are not exported. This is the default setting.

Current Design, Selected Projects and All Library Parts Complete design information for the current design is exported. Referenced designs that reside in a project selected for inclusion during export and are part of the current design's hierarchy are also exported. In addition, library parts are exported.

Project Hierarchy

Displays the current project. If hierarchical, all included projects are listed in the appropriate order.

Projects Included During Schematic Export

This field contains the projects for which schematic design information is exported. You can customize this list if the current project is hierarchical.
To add a project to this list:

In the Project Hierarchy list, click the desired project.
Click the Include button. The project is added to the Projects Included list.
To include all projects, click Include All .

To remove a project from the Projects Included list:

In the Projects Included list, click the entry you want to remove.
Click the Remove button. The project is removed from the list.

To remove all entries from the Projects Included list, click Remove All .
This is an example of using the Project Hierarchy and Projects Included During Schematic Export fields. First you make a project called Proj_A that includes several designs. Then you make another project called Proj_B and you want to reuse some of the designs from project Proj_A in project Proj_B . You can then include Proj_A in Proj_B by using the Include button to have access to all the designs in Proj_A after your export is complete.

Prompt for User Message

This option is selected by default. If the option is selected, a dialog will be brought up prior to the export of the layout and schematic files. You may enter as much text into this dialog as you want. The text will be stored in the design_info file that is created the to_mgc/<design>.hpxfer directory.

Completing the MGC/PCB Export

After specifying the export options, click OK in the MGC/PCB Export Options dialog box to save your settings or Cancel to retain the default settings. After clicking OK , you are returned to the Export dialog box. Click OK to begin the translation.

When translation is complete, an Information Message dialog box appears stating, IFF Export Completed. The IFF Export log window also appears. Review the log message searching for any error messages or warnings generated during export.