• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 84 subscribers
  • Views 405 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Decoupling Inductor on CC2834x-DIMM100 Board

stefan.noehammer
Prodigy 120 points


Hello,

I looked at the schematic&BOM of the CC2834x-DIMM100 Board. There is a 22µH Inductor in 0805size used for decoupling the 1.2V Corevoltage.

This Inductor is rated for 13mA. 

The datasheet of the 28346 says 335mA(@25°C) typical for Idd.

How does this fit together?

Thanks,

 Stefan

 

  • 0
    Genius 5170 points

    Well, I think the goal is to reduce the current ripple. The inductor should be in play only during noise or ripple because in a DC circuit inductor is shorted anyways. But it is not clear why the inductor current rating is low compared to maximum current it is expected to carry ... may be I am missing something ...hopefully TI hardware team will shed some light on this .....

  • 0 in reply to Arefeen
    Prodigy 120 points

    I think also that the inductors are for filtering the ripple.

    On the board the  Vcore-Pins are divided in 4 groups, so the current gets (hopefully) equal distributed over the 4 inductors. But this means ca. 80 mA  for the 13mA rated inductor.

    If the current of the inductor is that above the rated current, so there is no much inductance left...

     

    The local TI-FAE advise me to look here for that question, so I also hope to get an answer...

  • 0 in reply to stefan.noehammer
    Prodigy 30 points

    Coilcraft's 0805LS-223XJL is rated for 150 mA.  If it only needs to handle 80 mA rating it will hold the inductance easily.

  • 0 in reply to Christopher Hare
    Prodigy 120 points

    The BOM says for the Inductance "LQM21FN220N00L" which is 13mA rated. This should be wrong.

    So I'd like to know the hole idea to divide the Vcore into 4 section each with a Inductance 'filtered' is well thought out.

    In the "CC2834x-DIMM168" schematic the decouple-Cs are placed on the wrong side of the inductance, so I'm mistrustful about the usage of this inductance.

    Has someone used this circuit in his own hardware?

     

  • 0
    Prodigy 30 points

    Hello, Can you provide Molex TMDSDIM100CON5PK（DIM100） or DIM128 technical manuals!thanks!

    Best Regard.