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FPD-Link III Power Feed Inductor Network for Coax

Madhu Vatte
Intellectual 835 points
Other Parts Discussed in Thread: DS90UB914A-Q1, DS90UB913A-Q1

Hi,

We’re currently working on a few PCB designs that employ FPD-Link III with coaxial cable and we started our designs with the same 100uH/5.6uH/1K inductor-resistor arrangement found on the schematics of the DS90UB914A-Q1 and DS90UB913A-Q1 eval kits.  However, it’s becoming obvious that this arrangement consumes so much room on the PCB that we have to ask the question of whether there is another alternative to this inductor-resistor arrangement that doesn’t require as much space.  Any suggestions?

Thanks,

Madhu

 

  • 0
    TI__Genius 13475 points

    Madhu

    The inductor network that is on the DS90UB914A-Q1 was not optimized for small physical size.  If you send me an e-mail, I can share with you a new reference design that we are working on which uses smaller components.

    The important thing about the inductor network is that it provide low impedance at DC, to allow for efficient transfer of power to the serializer circuit, but also represent a high impedance at the frequencies where data is being transferred. Generally you want to make sure that the network represents more than 1000 ohms of impedance at frequencies above 1 MHz, while in operation.  Depending on your design there will be 200 - 500mA of current going through the inductors, and you need to make sure that this high impedance is shown with that current - often smaller inductors will saturate at these current levels.

  • 0 in reply to Mark Sauerwald88474
    Intellectual 835 points

    Hi Mark,

    I have sent an email to 'mark.sauerwald@ti.com'.  You can send the reference design to that email.

    Thanks

    Madhu

  • 0 in reply to Madhu Vatte
    Intellectual 835 points

    Hi Mark,

    Please let me know if there is any update on this.

    Thanks

    Madhu