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DS90UB913A-Q1: FPD-Link III switching

Felix Lazarev
Prodigy 20 points
Part Number: DS90UB913A-Q1

We're in need to switch the FPD-Link III signal between two UB913A sources. Can RF switch (AS169-73LF https://www.skyworksinc.com/-/media/SkyWorks/Documents/Products/1-100/AS169_200105E.pdf )  be used, as in attached schematics?

  • 0
    TI__Mastermind 18755 points

    Hello,

    I cannot say for certain that the switch between two serializers will work.  It appears to have an insertion loss near zero and a characteristic impedance of 50Ohms but I do not see how it affects return loss. Also it will need to be capable of accommodating the lower frequency backchannel.  If the switch is able to accomodate the backchannel and the system meets our requirements for return loss/insertion loss then it should be okay.  Which deserializer are you using? May it be better to use a DES with more RX ports?

    Regards,

    Nick

  • 0 in reply to Nicholas Darash
    Prodigy 20 points

    Thank you for your reply Nick,

    The switch is capable of transmitting the frequencies of 300khz and up. The VSWR at low frequencies is near 1.15:1. Return loss = -20log10((vswr-1)/(vswr+1)) equals to ~ -23dB.

    Due to the application limitations we have to use one coax to transfer alternatively two sources. The DES is DS90UB914A, but only one coaxial cable is provided, and dictated by the OEM. 

  • 0 in reply to Felix Lazarev
    TI__Mastermind 18755 points

    Hello,

    So it appears that the device meets our channel specs and in that case it should play fine with the devices.  However,  it is hard to say how the return loss/insertion loss of the entire channel will be affected.  I would still recommend that you test the system against the total IL/RL budget specs.

    Regards,

    Nick