HD3SS214: AUX configuration for HD3SS214 switch

Hai Van Phu

Prodigy 165 points

Part Number: HD3SS214

Hi,

I am making a 2x2 Displayport 1.4 switch (2 IN, 2 OUT) as shown below:

https://i.imgur.com/vqRvCep.png

In which, I use 2 re-driver at both ends of this switch. I'm confused about the AC coupling capacitors on AUX channel.

Should I implement it at either end or just one side (Sink or Source)?

https://i.imgur.com/T1LWPT2.png

Besides, with the pull up and pull down resistors on AUX channel, is it optional or mandatory?

And which line should be pulled by these resistors ((1) Between Source and SW, (2) Between 2 SWs, (3) Between SW and Sink)?

Thanks and best regards,

Hai

over 6 years ago

0 David (ASIC) Liu over 6 years ago

TI__Guru**** 176281 points

Hai

Does this thread answer your question: e2e.ti.com/.../799130

Thanks
David

0 Hai Van Phu over 6 years ago in reply to David (ASIC) Liu

Prodigy 165 points

Hi David,

This has solved my problem.

Thanks,

Hai

0 Hai Van Phu over 6 years ago in reply to Hai Van Phu

Prodigy 165 points

Hi David,

Let's see the figure below (like in the thread you sent me)

Could you please help me verify whether the AC coupling capacitors are sufficient for both Main Link and AUX channel in this link from the CPU to the Monitor?

And do we need to add pull-up and pull-down resistors on any AUX connection?

Thanks,

Hai

0 David (ASIC) Liu over 6 years ago in reply to Hai Van Phu

TI__Guru**** 176281 points

Hai

1. You don't need AC caps on point 1, since AC caps should already populated on the source TX

2. Point 2 should be DC coupled since it is already AC coupled at point 6

3. AUX should be DC coupled and no pullup/pulldown are needed since they are already inside the source and sink. But I would still design the board with 0 ohm resistor option for both the cap and pullup/pulldown just in case if I need it.

Thanks

David

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HD3SS214: AUX configuration for HD3SS214 switch