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Original question:

LMH0307: Serial data complement output.

LMH0307: Clarification on LMH0307 for 1:2 or 1:3 HD-SDI Splitter Application

arvind Prajapati
Prodigy 10 points
Part Number: LMH0307
Other Parts Discussed in Thread: LMH0340, LMH0344, SD307EVK

Tool/software:

Subject: Clarification on LMH0307 for 1:2 or 1:3 HD-SDI Splitter Application

Hello TI Team,

I’m planning to use the LMH0307 as part of a design where I need to split a single HD-SDI signal into multiple outputs (preferably 2 or 3), all with proper 75-ohm drive capability to connect directly to standard SDI monitors or equipment.

According to the datasheet, the LMH0307 accepts a differential SDI input, but in the typical application/reference design, I see a single-ended 75-ohm input being fed to the device. I would like to confirm:

  1. Can I provide a single 75-ohm SDI signal (AC-coupled) to the input of the LMH0307 as shown in the reference design and still meet the input requirements of the part?

  2. If I use two or three LMH0307 outputs driven from the same SDI input, can I achieve proper SDI fanout (i.e., identical SDI outputs on all channels)?

  3. Can the outputs of LMH0307 be connected directly to 75-ohm SDI monitors without any additional driver/buffer stage?

  4. Is there any recommended schematic or application note from TI specifically for a 1:2 or 1:3 HD-SDI splitter using LMH0307 or a similar TI part?

My goal is to ensure proper signal integrity across all outputs when splitting a single SDI input, and I would appreciate confirmation on whether LMH0307 suits this use case or if an alternative like LMH0340 or a true fanout buffer would be more appropriate.

Thanks in advance for your support!

Best regards,
Arvind 













  • 0
    TI__Mastermind 30130 points

    Hi Arvind,

    1. No, LMH0307 is intended for 50ohm impedance at the input. You could place LMH0344 before LMH0307 to convert 75ohm to 50 ohm single ended/100ohm differential.

    2. Yes, LMH0307 has two outputs. You can drive these both with the same SDI input to get the functionality like you describe.

    3. Yes the outputs are intended to drive 75ohms.

    4. I recommend validating your use-case with SD307EVK first to get a better feel for this device. The schematic for this EVM is included in the EVM user's guide.

    Best,

    Shane