[hpsdr] ATLAS Xbus and Ybus Impedances

[Ray Anderson]

HPSDR Group:

I had a little spare time this morning so I ran the ATLAS Xbus and Ybus
geometries through a transmission line modeler (Mayo TNT 1.2.2 BEM
extractor) to determine the Zo for the lines.

Assuming Er=4.2 (typical FR4) here are the numbers:

Ybus (internal stripline traces): 58 ohms

Xbus (surface microstrip traces): 78.5 ohms


While the current intent isn't to route any signals on the backplane
that depend on critical impedance control it is kind of nice to know
what we have. 

While not ideal, LVDS clocks could be routed on the internal Ybus layers
if necessary with some degradation of the signal integrity
characteristics of the signals.


73,   Ray   WB6TPU






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