TUSB211: Simulation

user4979999

Prodigy 690 points

Part Number: TUSB211

Hi team,

Please check customer question below. Thanks.

The TUSB211 is a USB2.0 repeater not MUX/Retimer.

The post channel result is based on the pre channel and repeater setting.

However, the model of TUSB211 is assumed the post channel has no relationship with pre channel.

The assumption is wrong and not able to simulate the real application.

Please check if the model has any update.

over 5 years ago

0 Malik Barton57 over 5 years ago

TI__Guru 64326 points

Hi,

TUSB211 does not have a traditional pre and post channel since in a real application USB 2 traces are shorted under the device.

0 user4409055 over 5 years ago in reply to Malik Barton57

Prodigy 35 points

Yes, the input and output pins are shorted by the TUSB211 footprint.

This is confused us, how to use the model to simulate USB2.0 signal? So far, the model is not able to simulate the ISI from pre-channel.

Please provide more detail about it.

0 user4409055 over 5 years ago in reply to Malik Barton57

Prodigy 35 points

Yes, the TUSB211 input/output pins are shorted by the footprint.

We are coufused by the design, how to use the model to simulate the channel with the prec-channel ISI?

Please provide more detail about it.

0 user4979999 over 5 years ago in reply to user4409055

TI__Prodigy 690 points

Hi Eriksson,

Please see below.

TUSB211 in real application will have DP and DM shorted on both sides of the device so there is no “traditional” pre and post channel. In the simulation provided the assumption is that TUSB211 is very close to a USB Host. Customer can add additional blocks to netlist to add loss in path if desired.

0 Malik Barton57 over 5 years ago in reply to user4979999

TI__Guru 64326 points

Hi Eriksson,

I want to align with you. Are you trying to create a eye diagram and measure the ISI? Are you try to simulate using the "pre-channel" s-parameter file?

0 user4409055 over 5 years ago in reply to Malik Barton57

Prodigy 35 points

We are trying to simulate a channel that has implement TUSB211.

I have two questions.

1. In traditional repeater case, we can saperate the channel to pre and post and add repeater model between pre and post to see the eye result.

But TUSB211 input/output pins are shorted by the footprint. How to simulate this situation?

2. The model of TUSB211 is like a signal host with any pre channel ISI effect. How to correlate the model to real measurement?

0 Malik Barton57 over 5 years ago in reply to user4409055

TI__Guru 64326 points

1. The test bench provided as an example of how this is done. TUSB211 will still influence the signal even when nodes are shorted.

2. You could measure the eye diagram with the TUSB211 very close to the USB Host or Hub to get the best correlation.

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TUSB211: Simulation