AM3356: Errors while IBIS model validation

Hello Arun,

Thank you for the query.

We are trying the validate the IBIS model 

Could you please elaborate your observations. 

Did you try any of the other models' below ?

https://www.ti.com/product/AM3356#design-tools-simulation

Regards,

Sreenivasa

Hi Sreenivasa,

Capacitance matrix issue got resolved using below tread.

https://e2e.ti.com/support/clock-timing-group/clock-and-timing/f/clock-timing-forum/906351/lmk04808-problem-with-ibis-model.

We have another issue while simulation. We have used zcz model from the link that you have provided. We are trying to simulate GMII_TXDx signals. We do not see any issue with slow and typical model but for fast IC model we see ringing without any trace length. if we do the simulation with trace on board this ringing increases even with 43Ohm of termination.

Hello Arun,

Thank you for the note. Let me check internally. 

Any reason to configure the ethernet TX as GPMC.

Have you tried configuring the processor  ethernet TX back to RX.

Here are the inputs i received for the initial query 

This is common and exists on other models as well. It is not an issue. Recommendation is to migrate to IBIS checker version 5 or newer.

Regards,

Sreenivasa

Hi Sreenivasa,

We have configured TX as GPMC because we are using two ports of ethernets. 

IBIS checker issue resolved after referring other thread and removing some section from the model.

@Naveen is working with me and he is facing few issues with AM335x and DP83848YB Ibis model. He will update on the thread with observation. Please suggest.

Hello Arun,

Thank you for the inputs.

Can you please share the thread that you referred.

Regards,

Sreenivasa

e2e.ti.com/.../lmk04808-problem-with-ibis-model

Hello Arun,

Received and thank you.

Regards.

Sreenivasa

Hi Sreenivasa, 
 I hope you have some clarification after Arun replies like why we are using GPMC. 

We are facing issues in IBIS models on the Ethernet interface.  we using both are TI models (Driver & Receiver)
CASE 1:



CASE 2:




Thanks in Advance. 

Hello Naveen, 

Thank you.

I am checking internally.

Can you please download AM625 or AM6448 model and do a quick check just to rule out any setup related issues.

Regards,

Sreenivasa

Hello Naveen, 

Please refer below inputs on the queries you had 

The IBIS models will contain package RLC data in addition to Tx I-V curves.

So some ringing is expected even without board traces if they are connecting Tx and Rx back-to-back.

The only suggestion would be to impedance-match the board traces as much as possible to the package traces and choose the appropriate termination.

 Regard,

Sreenivasa

Hi, sreenivasa, 

After your suggestion, we give a run with an alternative TI model (AM625. rev. b)

For, CASE 1: Ethernet TX -  we got a good output response attached below



For, CASE 2:    
 (I): Ethernet RX with actual PHY driver,                                     (ii) Ethernet RX with alternative TI model PHY driver                              
 


we believe both TI IBIS models are having issues. 
1. am335x_zcz
2. DP83848yb 

by using alternatives the results are compromised. 

Hello Naveen, 

Thank you for the inputs and running multiple iterations.

we believe both TI IBIS models are having issues. 
1. am335x_zcz
2. DP83848yb 

by using alternatives the results are compromised. 

Could you please elaborate  your observations.

Regards,

Sreenivasa