• State TI Thinks Resolved
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 65 views
  • Users 0 members are here
Support feedback
Options
Options
Related

DS30EA101: The DS30EA101SQ receives an SDI 1.5G signal from a 100Ω differential input and converts it to a 75Ω SDI output

Volodymyr Kornilov
Prodigy 10 points
Part Number: DS30EA101
Other Parts Discussed in Thread: DRIVECABLE04EVK,

Tool/software:

Hello
Could you help me understand why my schematic does not work?
I have a 1.5G SDI video signal coming from a shielded twisted-pair 20-meter cable with 100Ω impedance.
I want to convert this signal from differential to single-ended 75Ω for a BNC connector to a standard SDI monitor, and compensate for some signal loss with the DS30EA101SQ.
I see the SIGNAL LED turn on when I connect the differential 100Ω signal to the input, so it looks like the IC is detecting the SDI signal, but there is no video output.



For testing, to be sure that my idea is working, I used a small balun instead of the DS30EA, and I was able to get the SDI signal, although with significant losses. The monitor started showing an image.

  • 0
    TI__Mastermind 18850 points

    Hi Volodymyr, 

    The DS30EA101 LVDS output drivers have internal 100-Ohm terminations. Although the input of the DS320EA101 can accept 75-Ohm lines with appropriate receiver termination, I haven't seen examples in the datasheet or DRIVECABLE04EVK evaluation module showing how the output can be adapted for 75-Ohm lines. I don't have personal experience with converting LVDS line impedance from 100 Ohms to 75 Ohms, but I think it may be more complex than the series resistor with parallel inductor arrangement shown here. Maybe it would be necessary to install a balun after the DS30EA101.

    In typical applications, the DS30EA101 is placed after a cable and the output is expected to go directly to a differential receiver. It sounds like your use case may be different, with the DS30EA101 output going to another BNC cable before entering the monitor? The equalizer should still help the final signal quality but special treatment may be needed for the output stage to make sure the impedances are converted correctly.

    Best,

    Evan Su