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Welcome back to my blog series on Virtuoso® Module Generator (Modgen). In my first post, I gave an insight into the basic features of the tool and spoke about how Modgen provides tremendous advantages for analog layout automation. With changing demands, we’ve been continuously improving the Modgen tool to match the requirements.
In my second post, I spoke about an important new feature—Support for Stacked Devices in Modgen. Here’s my third post in the series, in which I’ll talk about the Layout Reuse Flow in Modgen, an important feature introduced for advanced-node PDKs.
Nowadays, everyone is talking about ‘reuse’—reuse plastic, paper, batteries, and so on. When we talk about software reuse, what we really mean is to create reusable software assets. The layout reuse flow in Modgen lets you extract layout characteristics in template form from existing Modgens or other groups of devices, which are the reusable assets. You can then apply these templates on new designs to create Modgens that are similar to the source. Isn't that convenient?
Here are the key advantages of the layout reuse flow:
It’s important to understand the flow before we talk about the implementation. So here you go…
Here's a flow chart that depicts the overall flow:
We know that Modgens can be created from either the Virtuoso Schematic Editor or the Virtuoso Layout Editor.
These extracted parameters are stored in a Modgen template file. You can run this template file on one or more target layouts to generate Modgens that are similar to the source layout.
This can be better understood using an example. In the following animation, the source is a layout view that contains a differential pair with dummies. Parameters are extracted from the source to create a Modgen template file, which is then applied to another differential pair to create a new Modgen that is similar to the source.
That’s how, with just a click of a button (or maybe a few clicks), you can create similar structural copies of a Modgen. It's that easy!
Do you want to create Modgens that are more-or-less similar, with slight changes, for example, in their pattern or abutment style? That’s also possible! Open the Modgen template file and make the required changes before generating a new Modgen. Having said that, let’s look at a Modgen template file and what information it contains.
A Modgen template file is a collection of parameters that can be used to create a gridded layout for matching structures. The file is in text format, and so is easily readable and editable. Modgen template files are stored at a convenient location for you to look at and customize as per your requirements.
Here are a few important Modgen parameters that are included in a Modgen template file:
Go ahead and try out this amazing new feature!
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