Stack Attributes Controlled by the Array Assistants

(Virtuoso Advanced Node for Layout Only or Layout Standard) Each abutted stack of devices in a Modgen is represented as a single symbol, as if it were a single device, in the Array Assistant.

You can use these assistants to customize the following stack attributes:

• Orientations of Stacks: A stack may have valid orientations of R0, MX, MY, or R180. The orientation applies to the entire stack; the orientations of the stack members may (or may not) be identical to the orientation of the stack. This means that the absolute orientation of a stack is arbitrary. Therefore, the displayed stack orientation may not always be preserved when the stack is rotated. When a stack is rotated, the orientation is applied to each stacked device individually. MY and R180 rotations also result in a left-to-right reversal of the ordering of the stack members.
• Stack Names: Stacks are named in one of the following ways:
  • If a naming pattern is recognized, then its base pattern is used to identify the stack.
    For example, a stack named M0 is created in the following situations:
    • A stack that represents the layout devices M0.0, M0.1, M0.2, and M0.3 that are bound to schematic device M0 with an s-factor.
    • A stack that represents iterated layout devices M0<0>, M0<1>, M0<2>, and M0<3>.
  • If a naming pattern is not recognized, then the stack name is based on the name of the first stack member, alphabetically.
• Dummies around Stacks: Dummies can be added around stacks.
  • Dummies added above or below a stack result in a stack of dummies with the same number of members as the reference stack.
  • Dummies added to the left or right of a stack result in a single dummy being inserted.
  • Surround dummies inserts dummy stacks above and below the stack and a single dummy on each side.
• Pattern Presets: Built-in presets, other than the resistor presets, support the use of Modgen sandbox objects in both, the stacked and unstacked formats. Resistor presets support only the unstacked format.

Related Topics

Support for Stacks in Modgens

Array Assistant

Automatic Generation of Modgens using the Array Assistant

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