TS3DV520: Cascading 4 channel CSI from four inputs to one output using three 2:1 multiplexers.

AJ Ratzlaff

Part Number: TS3DV520
Other Parts Discussed in Thread: TS3DV642

Hello,

I am designing a test board that requires a variety of throughput signals, but the one I'm struggling with is the MIPI CSI. I have four cameras that need to be tested, but only enough hardware to have one input. My current idea is to use a multiplexer, and it seems only 2:1 multiplexers exist for 10+ channels. Because I need to test four different 4 channel CSI signals, my thought is to use three 2:1 multiplexers in a cascade configuration. If this is unfeasible or there is a better way, I am all ears.

This is my rudimentary block diagram of how I think it could work.

Thank you in advance.

over 2 years ago

+1 David (ASIC) Liu over 2 years ago

TI__Guru**** 165681 points

Hi,

Please see this e2e link, https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1115970/ts3dv520-ts3dv520. You can use TS3DV642 to accomplish this. Each TS3DV642 adds certain amount of insertion loss. Depends on the data rate, I would add a retimer such as DPHY440 at the TS3DV642 output to provide signal compensation.

Thanks

David

0 AJ Ratzlaff over 2 years ago in reply to David (ASIC) Liu

Prodigy 30 points

If I understand correctly, it would be beneficial to add a retimer to the output of the last multiplexer in the cascade? Are there other things I need to add to this kind of circuit to ensure stability? I plan to add ESD diodes, but otherwise just pass through to these ICs.

0 David (ASIC) Liu over 2 years ago in reply to AJ Ratzlaff

TI__Guru**** 165681 points

Hi,

It would be beneficial to add a retimer to the output of the last multiplexer in the cascade -> This is correct.

Each MUX would add certain amount of insertion loss, so depending on the data rate, we want to make sure the total insertion loss (trace, via, connector, MUX, etc) before the retimer is kept within the retimer EQ compensation capability. For DPHY440, its max EQ compensation is 5dB at 1.5Gbps.

Thanks

David

0 AJ Ratzlaff over 2 years ago in reply to David (ASIC) Liu

Prodigy 30 points

Thank you for your assistance!

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TS3DV520: Cascading 4 channel CSI from four inputs to one output using three 2:1 multiplexers.