[hpsdr] ATLAS Xbus and Ybus Impedances

[Philip Covington]

On 3/22/06, Ray Anderson <ray.anderson at xilinx.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> 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

Good deal...

Seems like if we needed to get a clock signal through the bus we could
use the DS92LV010 transceiver since it will drive loads down to 10
ohms with no problem.

73 de Phil N8VB

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