TUSB211: How to remove the noise when applying higher EQ gain

Hi Chase,

Can you provide the Schematic or layout files for this design? Additionally, if there are any eye diagrams, that would also be appreciated.

Thanks,

Ryan

Dear Ryan,

Thank you for your support.

Here is the additional information you requested.

This information is confidential, so i will delete it after you download this file.

(file deleted.)

And here is another question from customer,

my customer wants to know that it is low logic signal or high logic signal which is in the red dotted box below.

Best regards,

Chase

Hi Chase,

It seems like this could be due to reflections in the signal, that plus the TUSB211 is not our best redriver for automotive use.

Where are you measuring the signal at? This can help us with determining what the signal should look like or what can be affecting it. A block diagram would be a good way to show this.

Additionally, if possible, I would recommend looking at the TUSB216-Q1, as it is a newer redriver in the same line and has been tested for automotive applications.

Thanks,

Ryan

Dear Ryan,

Thank you for your support.

Actually my customer used TUSB211-Q1 for their application, and the problem is that only over iPhone 12 cannot connect through TUSB211-Q1.

Could it be a reason of this failure because of the reflection?

we cannot fix it (remove this noise) through firmware or additional schematic?

what is the reason that TUSB216-Q1 is more suitable than TUSB211-Q1?

Cause end customer thinks that this is very urgent issue, so we think solving this problem is very important to us.

please check this issue. Thanks.

Best regards,

Chase

Hi Chase,

One thing that can cause reflections is an impedance mismatch. Would it be possible to verify that the impedances are being matched between the IPhones, Cables, and boards?

Additionally, if you can send the layout files, we may be able to look at the impedance of the design and see if there is an issue there.

Some differences between the TUSB216 and TUSB211 can be found here: e2e.ti.com/.../tusb211-request-to-check-the-difference-between-tusb211-and-tusb216

Thanks,

Ryan

Dear Ryan,

Thank you for your support.

As I said, disconnection only occurs over iPhone 12.

1. I saw the link that you mentioned, TUSB216 includes DC boost feature, and TUSB211 does not. does it affect to the performance of connecting and disconnecting?

2. do you have any impedance range of USB line for successful operation?

I will ask layout file to my customer.

Best regards,

Chase

Hi Chase,

1.) In the context of carplay, yes, I believe that the DC Boost feature would help with ensuring that carplay is functional for all phone models. That boost can help to meet the margins specified for carplay. It also just helps the signals in general.

2. Typically, USB 2.0 High Speed signals use a 45Ohm termination resistance for its signals. More details regarding this can be found here: https://www.usbmadesimple.co.uk/ums_6.htm

Thanks,

Ryan

Dear Ryan,

Thank you for your support. Test is going well so far.

I have one more question, do you have any document about the difference of AC boost and DC boost, and how they work both?

Cause end customer wanted this contents, and will have a meeting about this issue.

Please check about it. Thanks.

Best regards,

Chase

Hi Chase,

You can find more details regarding AC/DC Boost in this E2E: https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1119016/tusb212-tusb212-ac-boost-dc-boost?tisearch=e2e-sitesearch&keymatch=AC%2520Boost#

As you pointed out the TUSB216, as well as any redriver past the TUSB211, also performs DC Boost on signals, allowing for VHigh and VLow of diagrams to be boosted, giving more clearance to the eye. AC Boost mainly affects the rising and falling edges of the eye diagram.

Please let me know if there are any other questions.

Thanks,

Ryan

Dear Ryan,

Thank you for your support.

I am sorry but I cannot open the link which you gave to me. lease check it again.

I will ask more after I look the link above.

Best regards,

Chase

Hi Chase,

Hmmm, that's odd.

Here is a snippet from the thread that covers what AC/DC Boost do.

As for how the AC/DC Boost operate, there is not much more we can say other than current is injected into the signal that goes through the device in order to boost it.

Please let me know if there are any other questions.

Thanks,

Ryan

Chase, these waveforms that are captured, is the packet transmitted from the phone or the head unit? 

Dear WIN,

Yes, you are right. Please advise to clear this problem, although they already tested with TUSB216.

Best regards,

Chase

you didn't answer whether the packet is from the phone or it is coming from the head unit,