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TS3L100: Can I use the TS3L100 to switch fiber interfaces and RJ45 connector?

Part Number: TS3L100
Other Parts Discussed in Thread: DP83849IF

HI,

I am using a PHY chip  that supports 100Base-FX and 100Base-TX, I would like to know if the TS3L100 can be used to switch fiber interfaces and RJ45?
I see that the TS3L100 supports 10/100 base-T in the data sheet. But I do not know if it can support 100Base-FX data protocol. I think it can be applied like this. What do you think?

I'll appreciate your recommendations.

Thanks!

luojun

  • Hello Luojun,

    The answer is yes, but not you cannot pass 100Base-FX directly. TS3L100 is designed to pass 100 Mbps signals, but from a copper medium.  So if you want to use 100Base-FX with this switch, you first need to convert the fiber-optic signal to a signal that can be passed through copper.  One product that you may consider to help you do this is the DP83849IF.  Below I have listed some helpful links to guide you through using this particular device.  I would recommend reaching out to the respective product team's E2E forum if you have any questions regarding the DP83849IF.

    datasheet:

    Reference Design:

    TI Forum for DP83849IF:

    Also I would like to clarify the functionality of the TS3L100, it is simply a switch that allows an incoming electric signal to pass to one of two nodes.  The passed electric signal needs to be within the voltage, current, and frequency ranges specified in the datasheet.  The TS3L100 performs no processing of the signals, and its output should be a slightly attenuated version of the input.

  • Hello my friend,
    Thank you for your answer.
    Please forgive my poor English,I hope you can understand.
    DP83849IF has port A and port B.What you mean is that I can connect Magnetics+RJ45 with port A and the fiber transceiver with port B, but I can not use port A to connect Magnetics+RJ45 and fiber transceiver at the same time, and use TS3L100 to switch between these two interface?In this case,I can control the pin of FX_EN_A and TS3L100 by cpu.
    thanks
  • Hello user4626029,

    I think I may have led you astray.  The DP83849IF essentially will use the MII or RMII  communication protocol on one side of the device and use 100BaseFX or 100BaseTX on the other side as shown in Figure 1 below.  However to use the 100BaseFX, you will need to cascade an additional transceiver stage as shown below in Figure 2

    Figure 1

    Figure 2

    If I understand correctly, you are wanting to do something like Figure 3 below.  This is possible, but you need an optical transceiver to make it work correctly.  The way you can achieve what you want is to use an optical transceiver as seen in Figure 4.  To make an optical transceiver, you can use and LED as your transducer and cascade that with a op amp, comparator, or voltage translator to achieve the desired voltage level.  The following link has a good schematic for helping you figure out how to design your own transceiver.

    Figure 3

    Figure 4