HD3SS3212-Q1: Regarding the TDR

Niranth Sagar A

Part Number: HD3SS3212-Q1
Other Parts Discussed in Thread: HD3SS3212

Hello Team,

I saw in the Interafce Forum that HD3SS3212_Q1 works for the 100Ohms But i am seeing a dip till 85ohms, so can you just try to help me out here and i paste the image belaow for Ref.

Thanks and Regards,

Niranth Sagar

3 months ago

0 Arya Hussein 3 months ago

TI__Expert 8590 points

Hi Niranth,

Can you send what interface forum you have seen that says this information about 100Ohms? Also can you show how you are using the device? If a observation of a dip at 85 Ohms is being seen, this indicates a potential impedance mismatching.

Thank you,
Arya

0 Niranth Sagar A 3 months ago in reply to Arya Hussein

Prodigy 20 points

Hi Arya,

HD3SS3212: Questions regarding TI USB3.1 Mux HD3SS3212IRKS - Interface forum - Interface - TI E2E support forums Here I saw that and

I checked only by keeping HD3SS3212 model and I am using for the HSGMII Interface between MCU to ETH_SW through Demux(HD3SS3212)(100Ohms) and the Traces are routed at 100Ohms.

With the Demux model there is some dip and Rise in Impedance.

Whether this model is matched to 100Ohms or 85Ohms Can you please confirm with this?

Thanks and Regards

Niranth Sagar

0 Arya Hussein 3 months ago in reply to Niranth Sagar A

TI__Expert 8590 points

Hi Niranth,

Is your application used for USB3.0, if so a recommendation of 90Ohm differential, with +/- 15% variance. You can find our design guidelines for USB3.0 in this datasheet: https://www.ti.com/lit/an/slla414/slla414.pdfts=1733766272554&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FHD3SS3212

The 100Ohms should not be a issue however I would model match with 85Ohms to see if dip is not seen anymore. 100Ohm +/-15% would be around 85Ohms.

Thank you,
Arya

0 Niranth Sagar A 3 months ago in reply to Arya Hussein

Prodigy 20 points

Hi Arya,

I need an 100Ohms Model because our standard is of +-10%(90 to 110Ohms), Can you model it to 100Ohms and share it to me is that possible?

Thanks and Regards

Niranth Sagar

0 Arya Hussein 3 months ago in reply to Niranth Sagar A

TI__Expert 8590 points

Hi Niranth,

I will see if we have any information on the model at all. Also from the image provide what is the rise time seems very quick, would it be possible to have a longer rise time?

Thank you,
Arya

0 Niranth Sagar A 3 months ago in reply to Arya Hussein

Prodigy 20 points

Hi Arya,

I kept for 100ps

How much rise time will you suggest me to keep?

0 Arya Hussein 3 months ago in reply to Niranth Sagar A

TI__Expert 8590 points

Hi Niranth,

For clarification you had the 100ps for the figure shown previously, correct? 100ps is a reasonable time, but I will investigate if this device would need a longer time.

Thank you,
Arya

0 Arya Hussein 3 months ago in reply to Arya Hussein

TI__Expert 8590 points

Hi Niranth,

I am still looking internally into this matter, it may be that this file may have a issues doing time domain analysis but I am verifying.

Thank you,
Arya

0 Arya Hussein 2 months ago in reply to Arya Hussein

TI__Expert 8590 points

Hi Niranth,

I was able to do a simulation for the TDR, below is my results:

**Please note this single port and not differential.
However this does not seem to fit within your +/- 10%.

Thank you,

Arya