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LMK03328: The power up sequence of VDD_PLLX, _IN, _DIG=3.3V and VDD_01, -_x=1.8V

Part Number: LMK03328

Hi all

Would you mind if we ask LMK03328?

There is the power up sequence on the data sheet Figure.86.




On the customer's board, the power up sequence  of VDD_PLLX, _IN, _DIG=3.3V and VDD_01, -_x are starts up the same timing.
Is there any trouble?
Or we have to proceed the sequence 3.3V -> 1.8V definitely like as Figure.86?(Because, protection diodes connect to each power rail,,,,)


Kind regards,

Hirotaka Matsumoto

  • Hello Matsumoto-san,

    It's okay to ramp-up all power-supplies at the same time. Please make sure that the PDN pin is released after all supplies have reached 95% of the final value. This is be either done by delaying the control signal from host controller or adding a capacitor to GND on PDN pin (if PDN is pulled-up by a resistor).

    Best regards,

    dinesh.