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Back drilling vias to remove stubs

Question asked by dave_kohlmeier on Oct 29, 2008
Latest reply on Nov 16, 2009 by dave_kohlmeier


We recently received a comment from a customer explaining how they had problems on a high-speed backplane and were able to reproduce the problem with HyperLynx simulations. But since the board was already produced it was too late to use blind and burried vias in a redeisgn. They found with HyperLynx via modelling that backdrilling would eliminate the SI problem. Without doing a redesign, backdrilling solved the SI problems and the backplane works.  The customer exported the net from a postlayout analysis into prelayout so he could edit the padstack.



A faster way might be to have the ability to do a "quick edit" of a specific padstack in postlayout simulation........



So my question:  How many of you out there are using backdrilling to overcome SI problems at high speeds?     Did you simulate the effect first?