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SN65LVDS391: Recommended Stack up

MuxV
Prodigy 60 points
Part Number: SN65LVDS391

Hello,

I'm trying to design a TTL to LVDS interface using SN65LVDS391 IC. I'm making the PCB a 4 layer board, with top layer for lvds, bottom for TTL, layer 2 for ground and layer 3 for power. The data sheet says to keep the separation between ground and power plane as 5 mils. But standard core sizes are around 47 mils. If i do change this to the separation suggested by TI, I have to increase the size of my dielectric spacing between the top and layer 2, and bottom and layer 3. I'm using sma connectors in the design, so i'm not sure if i reduce the board thickness further, will there be enough support mechanically.

Is there a reference/layout stack up that is recommended by TI for these ICs ?

It would be great if someone is able to guide !

Thank you,

  • 0
    TI__Genius 10250 points
    Hello,

    The recommendation in the datasheet of 5 mil separation between power and ground planes is to provide more distributed bypass capacitance. I would make it as tight as possible while considering your other requirements, and make sure you have enough bypass capacitance. Follow the guidelines on bypass capacitance (section 11.2.1.2.2) in the datasheet.

    Regards,
    Yaser