Folding a Multi-fingered Device to Create Split Fingers

The Split fingered devices option controls whether each finger of a schematic device is placed in the layout as a separate device. If a multi-fingered device requires to be split after the device has been generated in layout, you can fold the multi-fingered device in order to create a separate device for each finger.

To fold a multi-fingered device or transistor:

1. In the schematic or layout canvas, select the multi-fingered device you want to fold.
2. Choose Connectivity – Generate – Folded Devices.
   The Generate Folded Devices form is displayed.
   The number of existing folds is displayed in the Number of Folds. Folding creates a new device for each fold by setting the Fingers parameter to 1. By default, the width of each new device relies on the fingers callback of the PDK to set the correct width. By setting the environment variable foldFingerSplitUseSchWidth to t, you can specify that the width be calculated by dividing the schematic instance by the number of fingers and applying the calculated number to the width of each new device created.
3. Click Apply in the form and move the cursor into the layout canvas. The outline of the folded device follows the cursor in the canvas.
4. Click in the layout where you want to place the folded device.
   The folded device is placed in the canvas. The original device orientation is preserved. The net on the left of the device (or on the bottom for vertically-oriented devices) is the same before and after folding.
   The Split Fingered Devices option in CPH is automatically set for that device. This means that if you delete and regenerate the layout view, the CPH settings are retained and each finger of the multi-fingered device will automatically be placed in the layout as a separate device.

Related Topics

foldFingerSplitUseSchWidth

Connectivity Form

Splitting Fingered Devices

Generate Folded Devices Form

Folding a Transistor or FinFET Device

Split-Fingered Device Folding

Folding a Multi-fingered Device to Create Split Fingers

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