Surround Modgen Form

Use the Surround Modgen form to add surround dummies around Modgen instances. The form includes a few common fields and a few tabs. The following table describes the common fields in the Surround Modgen form, which are available only in the Virtuoso Advanced Node for Layout branch.

Field	Description (Virtuoso Advanced Node for Layout)
Default values	Provides a list of presets that have been registered using a SKILL callback function. This is helpful when you want to apply the same style across designs. You can load the values and edit them as per your requirement.
Load	Loads values from the selected preset.
Top	Adds dummies to the top of the selected Modgen instances.
Left	Adds dummies to the left of the selected Modgen instances.
Right	Adds dummies to the right of the selected Modgen instances.
Bottom	Adds dummies to the bottom of the selected Modgen instances.

In addition to the above fields, the Surround Modgen form contains the following tabs.

Tab	Description
Master	Specifies the cellview to be used to create custom dummy devices.
Parameter	Specifies the dummy parameters.
Connectivity	Specifies the connectivity settings for the dummies.
Tap	(Virtuoso Advanced Node for Layout) Specifies settings for inserting tap cells.

Master

The following table describes the fields available on the Master tab of the Surround Modgen form.

Field	Description
Library	Specifies the library that contains the required dummy instances.
Cell	Specifies the cell that contains the required dummy instances.
View	Specifies the view that contains the required dummy instances. View lists only the `maskLayout` type views.
Browse	Opens the Library Manager from which you can select the required cellview.

Parameter

The following table describes the fields available on the Parameter tab of the Surround Modgen form.

Field	Description
Num Fingers	Specifies the number of fingers in each dummy. You can either type the required value in the field or choose from the following values: Same As Neighbor: The same number of fingers as the neighboring device are created. CDF Default: The default number of fingers, as specified in the CDF, are created.
Length	Specifies the length of dummy fingers. You can either type the required value in the field or choose Same as Neighbor or CDF Default.
Width in IC6.1.8; Number of Fins in Virtuoso Advanced Node for Layout	Specifies the width of dummy fingers. You can either type the required value in the field or choose Same as Neighbor or CDF Default. In Virtuoso Advanced Node for Layout, the Width cyclic field is replaced by the Number of Fins cyclic field. Valid values are the same as Width.

Field

Description

Num Fingers

Specifies the number of fingers in each dummy. You can either type the required value in the field or choose from the following values:

Same As Neighbor: The same number of fingers as the neighboring device are created.
CDF Default: The default number of fingers, as specified in the CDF, are created.

Length

Specifies the length of dummy fingers. You can either type the required value in the field or choose Same as Neighbor or CDF Default.

Width in IC6.1.8;

Number of Fins in Virtuoso Advanced Node for Layout

Specifies the width of dummy fingers. You can either type the required value in the field or choose Same as Neighbor or CDF Default.

In Virtuoso Advanced Node for Layout, the Width cyclic field is replaced by the Number of Fins cyclic field. Valid values are the same as Width.

Connectivity

The following table describes the fields available on the Connectivity tab of the Surround Modgen form.

Field	Description
Default	Specifies the net to which all dummy terminals must be connected. If left blank (no net is selected), no terminals are created.

Tap

(Virtuoso Advanced Node for Layout) The following table describes the fields available on the Tap tab of the Surround Modgen form.

Field	Description
*Between Rows*	Specifies whether dummies are to be inserted between rows.
Starting Row Index	Specifies the first reference row for inserting dummies.
Rows to skip between insertions	Specifies the gap (number of rows) after which dummies must be inserted.
Between Columns	Specifies whether dummies are to be inserted between columns.
Starting Column Index	Specifies the first reference column for inserting dummies.
Columns to skip between insertions	Specifies the gap (number of columns) after which dummies must be inserted.
*Row Configuration*	Lets you specify dummy row settings.
Single Dummy Row	Inserts a single dummy row, instead of individual dummies, in each direction. The available options are: Auto automatically calculates the number of fingers to be included in a dummy row. Specify lets you specify the Total Number of Fingers Per Row.
Total Number of Fingers Per Row	Specifies the number of fingers to be included in a row of dummies.

Virtuoso Module Generator User Guide
Product Version IC23.1, November 2023