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UltraZed-EG SOM Routed Net Length (Trace+ Package Delay) Calculation

7beedle

Can you please provide the steps/ calculations necessary to calculate the Routed Net Length Column of Table 23: – UltraZed-EG SOM JX1/JX2 Routed Net Length of the Designer Guide?

 

It lists the Column as Routed Net Length: (Trace + Package Delay) and units are in mils.  Of specific interest is the Package Delay portion of the calculation.  Is this using the flight time calculations from Vivado and applying what constant to achieve the length for the delay portion?

Also in section 9: JX1, JX2, and JX3 Routed Net Lengths: The section describes the tables as showing the routed net length from the Zynq to the JX1, JX2 & JX3.  But tables 24, 25, 26 list them as Package Delays (mils)

Please help clarify.

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    Hello 7beedle,

    The EG is routed by groups. So, the simplified table 23 shows the average delay across the group, ie 1969mils for JX1_HP_DP_[00:07]_P/N .

    The larger table 24, 25, 26 shows the individual delay across every net to the JX connectors. These may vary by a few mils across the group but as a whole exist right around the group delay number presented in the first table listed.

    Depending on required performance, a customer could use the group delay number or the more accurate tables from section 9.

    The section 9 table headers appear to be mixed up. My apologize we will work on getting this corrected. In the mean time, the three headers should read Package Delay / PCB Trace Length / SOM Total Trace Length.

    Please refer to these headers 

    image

    These are all trace delay + package delay = SOM Total Trace Length (using conversion from ps to mils).

    Thanks,

    Josh