Using the Electric VLSI Design System

Chapter VII: DESIGN ENVIRONMENTS

Lambda



To allow scalable designs, the term lambda is used to refer to 1 grid unit of layout. The grid display and alignment all use this unit to describe sizes. In order to translate this to real units, lambda has a value which is measured in database units (usually half-millimicrons). The number of microns per lambda unit is shown in the status area under the heading "LAMBDA".
You can change the value of lambda with the Change Units... command of the Technology menu. A dialog is presented in which the current value is shown and a new value may be typed.

Besides changing the value of lambda, you can also change the internal units and the display units. Be careful if you change the internal database unit, because this may result in all data being scaled which may not be desirable.

When you change the display units, it only affects how numbers are presented, not their internal storage. For example, selecting the "Microns" display unit causes Electric to describe distances in microns, rather than lambda units. When a real display unit is used, appropriate notation is used to express distances (i.e. a 3 micron wire is "3u" wide).


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