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LMK03328: Split power supply and PDN pin

Kawai
Guru 19785 points
Part Number: LMK03328

Hi Team,

I have questions about the device behavior. What could occur in below cases ?

[Case 1]
- LMK03328 used in split power supply, VDD_xx=3.3V and VDDO_xx=1.8V.
- PDN pin is pulled up to VDD_DIG/PLL1/PLL2 pin.
- 3.3V ramps up first, then 1.8V ramps up.

[Case 2]
- LMK03328 used in split power supply, VDD_xx=3.3V and VDDO_xx=1.8V.
- PDN pin is pulled up to independent 3.3V rail.
- VDD_xx=3.3V ramps up first, independent 3.3V ramps next, then VDDO_xx=1.8V ramps up.

Could there be a possibility that the device could get damage or fail to power up ?

Best Regards,

Kawai

  • 0
    TI__Genius 11900 points

    Hello Kawai,

    According to 12.4.2. Power-On Reset there are certain conditions that need to be met before the device is released from reset. Please refer to these.

    Both of these cases do not seem to be violating 8.1 Absolute Maximum Ratings.

  • 0 in reply to Vibhu Vanjari
    Guru 19785 points

    Hi Vibhu-san,

    Thanks for your comment.

    This is related question to my another post.

    In Case 2, VDDO_xx  is 1.8V and PDN pull up voltage is 3.3V.

    As long as I see the absolute maximum rating specification, this seems to be acceptable.

    However, there is internal 200kohm pull up to VDDO_01, so, there should be a leak current of (3.3-1.8) / 200k = 7.5uA.

    Can we ignore this leak current ? Any side effect used in this case ?

    Best Regards,

    Kawai

  • 0 in reply to Kawai
    TI__Genius 11900 points

    Hello Kawai-san,

    There should not be any side effects with pulling PDN to VDD_x (3.3V).

  • 0 in reply to Vibhu Vanjari
    Guru 19785 points

    Hi Vibhu-san,

    Thank you so much for the support !!

    I understood that PDN pin could be controlled from 3.3V bus even used in split supply.

    Best Regards,

    Kawai