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DS15BR400 Lvds buffer/repeater Overheat

Fabrizio Viotto
Prodigy 30 points

Other Parts Discussed in Thread: DS15BR400

Hello !

We are developing a new projects, and we have chosen to evaluate the component DS15BR400 to drive three four channels LVDS lines.

We have valuated the DS15BR400 4-Channels LVDS Buffer. But this buffer/repeater overheat.

With a Ta = 25°C (77°F), the component reaches a temperature of 70°C (158°F) using a transfer speed of 500 Mbps and VDD = 3.3V.

Is that correct? We must expect less warm?

thanks for the support in advance,

kind regards.

  • 0
    TI__Genius 13475 points

    Under normal operation, we would expect the DS15BR400 to dissipate ~500mW, which should make the part warm, but not hot.

    A few things to check:

    Other than the temperature is the device operating as you would expect?

    Are the signal levels at the input and output as you would expect?

    If you are able to monitor the supply current to the device, is that as you would expect (~200mA)

    Are the data inputs/outputs AC coupled?

     

  • 0 in reply to Mark Sauerwald88474
    Prodigy 30 points

    Hello,

    Thank you for your answer.

    Here my answers:

    Other than the temperature is the device operating as you would expect? YES

    Are the signal levels at the input and output as you would expect? YES

    If you are able to monitor the supply current to the device, is that as you would expect (~200mA) THE CURRENT ARE 160mA WITHOUT DATA TRANSFER AND 200mA WHEN A 500 MBPS LVDS LINE IS ON.

    Are the data inputs/outputs AC coupled? NO

    THANK YOU AGAIN FOR YOUR HELP

    FABRIZIO

  • 0 in reply to Fabrizio Viotto
    TI__Genius 13475 points

    Fabrizio

    It looks like the device is dissipating about the expected amount of power, so if it is getting hotter than we would expect, I would look at the thermal coupling of the device.

    The DS15BR400 device is in a QFN package.  The primary thermal path for this type of package is from the die, to the Dia Attach Paddle (DAP), which is exposed on the bottom of the part, and generally connected to GND, and the heat is dissipated into the ground plane on your board.

    Is it possible to check how well the DAP is soldered to the GND plane beneath the part? - If there is not a good thermal contact here, that may be causing the unexpectedly high temperatures that you are seeing.

    Mark

     

  • 0 in reply to Mark Sauerwald88474
    Prodigy 30 points

    Hello Mark,

    We are using the TQFP package. No GND plane under the package is required.

    Thank you again for your support

    Fabrizio