Configuring Shield Wires

To uniquely define the shield constraints for a net, do the following:

1. Create a new constraint group:
   

   create_constraint_group -name s_shieldGroupName 

2. Assign the new constraint group as the shield group for the nets that you want to shield.
   

   set_constraint_group -shield s_shieldGroupName -net s_netName 

3. Add constraints for the appropriate layers to the new constraint group.
   • Specify minWidth and minSpacing if you are adding parallel shields and/or tandem split shields.
   
   

   set_layer_constraint -layer s_layerName -constraint minWidth -Value f_value -group s_shieldGroupName 

   set_layer_constraint -layer s_layerName -constraint minSpacing -Value f_value -group s_shieldGroupName 

   • Specify tandemWidth, tandemLayerAbove, and tandemLayerBelow if you are adding tandem shields.
   
   

   set_layer_constraint -layer s_layerName -constraint tandemWidth -Value f_value -group s_shieldGroupName 

   set_layer_constraint -layer s_layerName -constraint tandemLayerAbove -LayerValue s_layerName -group s_shieldGroupName 

   set_layer_constraint -layer s_layerName -constraint tandemLayerBelow -LayerValue s_layerName -group s_shieldGroupName 

   • Specify tandem and parallel shield constraints, given above, if you are adding coaxial shields.

If constraints are not set in the shield group for the net, the shields will inherit the constraint settings from the signal net, the default, design, and foundry group, in that order. You can also specify unique shield options for individual routes in the net as described in Shielding by Route.

Related Topics

Controlling Shield Options

Shielding by Route

Setting the Shield Type

Shield Routing Script Examples

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