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Original question:

LMG3410R070: LMG3410R070

LMG3410R070: 5VLDO dropping

MarBel
Prodigy 50 points
Part Number: LMG3410R070

Hi

Could you please share any information from the webex meeting mentioned in the thread:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1067894/lmg3410r070-lmg3410r070?tisearch=e2e-quicksearch&keymatch=LMG3410R070:%20LMG3410R070

I am in a similar situation. The component shortage forced me to not use the designed in digital isolator ISO7721FDWV but instead the ADuM2286CRIZ. That seem to be a much more powerhungry device. I can see the 5VLDO output drop. 

I am now considering to add a separate 12V to 5V LDO on all FETs in the H-bridge and only use the in FET LDO to be connected to a 1uF cap and /LPM

Any light you can shed on the matter would be appreciated

Best regards

MarBel

  • 0
    TI__Intellectual 1341 points

    Hi MarBel,

    Thanks for your question. I will check with the team to provide you an answer tomorrow.

    Thanks,

    Noah

  • 0 in reply to Noah Rodriguez
    TI__Intellectual 1341 points

    Hi Marbel,

    That would work. Alternatively you could use ISO6721F instead of your switching frequency and slew rate are too small. You could also use the UCC14240 to generate both the isolated 12V and 5V using a single chip.

    Thanks,

    Noah

  • 0 in reply to Noah Rodriguez
    Prodigy 50 points

    Hi and thanks for the update

    I am still interested in what came out from the webex meeting mentioned in the other thread.

    Looking at the ISO6721F, it does look interesting and i might use that as an alternative mounting part.. I am however still worried about the LDO in the LMG34100R070. It provides 5mA and that seems low for most isolators. 

    The UCC14240 does look interesting, but i will not lock up my design on more single source solutions.

    Best regards

  • 0 in reply to MarBel
    TI__Intellectual 1341 points

    Hi Marbel.

    I do not remember the specifics of that Webex meeting as it was over 6 months ago.

    However, the 5mA should be more than enough for the isolator at lower speeds. For example, according to the datasheet for the ADuM2286CRIZ, it would be fine for below around 75Mbps.

    Thanks,

    Noah