Cadence PCB Best Practices

Working with Backdrilling

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Working with Backdrilling in Allegro PCB Designer: Best Practices Learn more at Cadence Online Support https://support.cadence.com © 2014 Cadence Design Systems, Inc. All rights reserved worldwide. Page 39 Note: The layer pair shift resulted in a couple of bottom side backdrill layer pairs to be combined with all others shifting up or down one layer depending on the backdrill side. To Layer Must Not Cut Layer Plunges To Layer Must Not Cut Layer Plunges LAYER_7_P LAYER_6 10 → LAYER_7_P LAYER_6 21 LAYER_6 LAYER_5 11 Tool Tip – Once the layers pairs are regenerated, Backdrill will be out of date. Select the Backdrill button to regenerate backdrill data for pins/vias using the new layer pairs. • With the "BACKDRILL_LAYER_PAIR_ADJUSTMENT" environmental variable set, you will see the following message. Select the OK button to continue. In the backdrill analysis log, the Remaining Stub Len column will report the distance from the shifted Must Not Cut Layer to the actual connection layer. Tool Tip – The Remaining Stub Len column is the distance from the shifted Must Not Cut Layer to the actual connection layer. ("To Layer" + "Dielectric" thickness). Maximum PTH Stub column is the Electrical Stub defined on the net using the BACKDRILL_MAX_PTH_STUB Property.

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