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SMA Connector Layout

A project log for USB Type-C Breakout Board

This board breaks out a USB Type-C plug to pairs of SMA connectors for each of the super speed pairs, a USB micro B connector for D+/-, and

greggreg 07/18/2019 at 03:440 Comments

SMA connectors are quite common for high speed interconnect in applications like this and you would think there would be plenty of app notes or examples to copy, but I was surprised how difficult it was to find a suitable reference to copy.  I did find some information online to point me in the right direction.  One issue I wanted to address was the fact that the pad for the signal pin is significantly wider than the trace width for a 50 Ohm trace.  This article by Dr.  Howard Johnson describes some techniques to deal with this ( http://www.sigcon.com/Pubs/edn/TaperedTransitions.htm ) I'm not going to go full tapered, but I did round the pad and cut away a little off the plane below to reduce the effect of the transition. 

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