TMUXHS4612: HDMI switch

Hi Mariusz,

Are you able to send a block diagram of the system you're looking to design? I'm struggling to picture this.

What speed of HDMI are you planning to use? 

Hi Vishesh, thanks for reply. I am looking for something like that in order to duplicate the signal and then switch between all of the signals to specific screen:

block diagram with TMUXHS4612 for 2 in 2 out.drawio.pdf

And this will be the prototype for more complex matrix like that:

block diagram with TMUXHS4612 advanced.drawio.pdf

HDMI speed I want to use is 48Gbps, which gives 16 Gbps for lane 3 lanes or 12 Gbps for 4 lanes.

Hi Mariusz,

Yes this is possible with the TMUXHS4612. This MUX has a maximum datarate of 20Gbps per lane.

However, adding this many muxes to the signal path will result in serious signal degradation. A retimer/ redriver is required. However, TI does not have parts that can provide this function at this high of a HDMI datarate. 

Who is the end customer of this design? The speeds proposed are outside of the HDMI2.1 specification.

I am aware of signal degradation, but I will give it a try for now. To be honest the end customer will be myself. I work a lot with multiple devices which I need to switch to both displays and it's getting me frustrated to use both commercial hdmi switches and switching between inputs on display. I've searched for such devices in web, but prices are too high for me, so I've started thinking of something that I can prepare myself.

Hi Mariusz,

I see. In that case why is the datarate required so high? What is the resolution you are pushing onto the two monitors?

It's because I am testing some more high end setups of PCs before I send them to customers just to be sure everything is working fine, but the more annoying reason is that I am working from home and my kiddo is using those monitors to play some games, so I want tokeep basic resolution that he has directly connecting PC to display to avoid his laments once I will use this kind of switch...

Hi Mariusz,

For the data rates you are planning to use 12Gbps per lane. This is pushing right around 4k 120hz.

This mux system will most likely eat up into the margin of the HDMI signal. If going at 4k 60 or maybe 2k 120 this mux should have sufficient margin.

Are you willing to slightly drop resolution for high frame rate/ or keep resolution at lower framerate?

With that many muxes its not possible to have both >100Hz framerate and >4k resolution at the same time.

I am thinking about ultrawide 1440p144Hz and standard 1440p at 120Hz

Yeah with 1440p/ 2k the losses of the mux should be acceptable.