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Registered: ‎10-12-2018

UltraScale IBIS-AMI TX Termination model issue


It was my understanding that the output of the GTH Tranceiver should output around 900 mV under the worst case PVT corner (FAST).

   Assumptions: Models are from Xilinx_UltraScale_GTH_AMI_Kit_Ver3p1p1

TXDIFFCTRL = 15, TXPOST =0 , TX PRE = 0, RX termination = 100 ohms 

Is this correct?  When I ran a simulation in HL VX 2.6, I was very shocked to see how low the output was at the end of my transmission line.  I removed my transmission line and the package model and simply connected the driver + its term block and got a eye height of 490 mV.

I removed the term block and got and eye height of 980 mV but the signal had some obvious reflections in it.

Is the worst case output for the driver really 490 mV?? Or am i using the termination-s parameters incorrectly?



Michael Darlington




HL Block Diagram w_term block.JPG
1 Reply
Xilinx Employee
Xilinx Employee
Registered: ‎06-01-2017

Hi @michael.darlington 

There are additional steps to be taken if you would like to probe intermediate nodes in Hyperlynx. See instructions below.


Advanced feature: How to probe intermediate nodes in the channel?

In HyperLynx simulation, additional steps are required if the user wants to probe intermediate nodes in the channel:

  1. Remove the RX AMI and .dll files in the IBIS-AMI channel analyzer
  2. Instantiate a dummy differential IC model at the probe of interest

The eye diagrams of intermediate nodes are only accurate if the 2 steps above are followed. See the example schematics below:

Don’t forget to reply, kudo, and accept as solution.