TMUXHS4212: MUX recommendation for FPDLINK 4

Hi Daniel,

For FPD-Link4, I believe the best recommendation we can make is the TMUXHS4412, which is a 20Gbps mux we have recommended in the past for FPD-Link4: https://www.ti.com/product/TMUXHS4412

While this much is not Q1-graded, it does support automotive temps, and there is an S-parameter available on the product page to test.

Please let me know if you have any other questions.

Thanks,

Ryan

Hi Ryan:

Thank you for your answer. I have the following questions that need your help.
1. Does this TMUXHS4412 chip only support differential signals? If my FPD-LINK output is a coaxial signal, can it be supported? If it cannot support coaxial signals, are there any other ICs that support it?
2. Does each channel port of this chip support bidirectional transmission? Can it support the forward transmission of FPDLINK video data stream and the reverse channel transmission of I2C signal at the same time?
3. This chip has 4 channels (D0x~D4x). Are these 4 channels independent of each other? Can I use them arbitrarily?

Hi Zhaomeng,

zhaomeng Su said:

1. Does this TMUXHS4412 chip only support differential signals? If my FPD-LINK output is a coaxial signal, can it be supported? If it cannot support coaxial signals, are there any other ICs that support it?

For coaxial/single-ended signaling, you can route through the + lanes of the mux, and leave the - lane floating.

zhaomeng Su said:

2. Does each channel port of this chip support bidirectional transmission? Can it support the forward transmission of FPDLINK video data stream and the reverse channel transmission of I2C signal at the same time?

This mux does support bidirectional, yes, however, do you mean simultaneous bidirectional signaling? I believe it would support it, but I can double check.

zhaomeng Su said:

3. This chip has 4 channels (D0x~D4x). Are these 4 channels independent of each other? Can I use them arbitrarily?

It depends what you are looking for. You cannot control each channel independently, I.E D0 going to D0A and D1 going to D1B, but each channel does not have to all be the same signals, I.E One channel can be coax signal, the other can be I2C.

Please let me know if you have any other questions.

Thanks,

Ryan

Hi Ryan:

Thank you for your answer.

1. For coaxial/single-ended signaling, you can route through the + lanes of the mux, and leave the - lane floating.

SU: OK, thanks.

2. This mux does support bidirectional, yes, however, do you mean simultaneous bidirectional signaling? I believe it would support it, but I can double check.

SU: YES, I need it to support bidirectional data transmission so that I can use it on the output link of FPDLINK IV. Is your double check result in support?

3. It depends what you are looking for. You cannot control each channel independently, I.E D0 going to D0A and D1 going to D1B, but each channel does not have to all be the same signals, I.E One channel can be coax signal, the other can be I2C.

SU: OK, thanks.

Hi Zhaomeng,

zhaomeng Su said:

SU: YES, I need it to support bidirectional data transmission so that I can use it on the output link of FPDLINK IV. Is your double check result in support?

I believe the mux should support it, there's nothing with it that would bar this signal from working. One point I was thinking of is that I2C lines typically require pull-ups, and video signals tend to be AC Coupled. Will either of these points affect the other?

Thanks,

Ryan

Hi Ryan:

Thank you for your answer.

At this point the I2C signal has been packaged in the FPDLINK protocol's reverse channel data packet via the Serializer and Deserializer. I think it will not be affected by the pull-up, right? Therefore, I think it can meet my application needs.

Hi Zhaomeng,

I agree, I don't believe there should be any issues. If there is no pull-ups in the actual path of the mux between the Ser and Des, I believe it should be okay.

Please let me know if you have any other questions.

Thanks,

Ryan