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LMK03328: Reset the device

Part Number: LMK03328

I have a question about I2C access failures. In another thread, we found an I2C access failure event with a frequency of 1/1000.

LMK03328: POR spec - Clock & timing forum - Clock & timing - TI E2E support forums

We too have confirmed the same event.
Therefore, we are trying to avoid this event by turning off/on the device power supply. In that case, is it OK to turn off/on only the following 4 power supplies for input?
(Power supplies for input: VDD_IN, VDD_PLL1, VDD_PLL2, VDD_DIG)

Because of only one power supply system for output (specifically, VDDO-7=1.8V, the rest are 3.3V)) is supplied from another power source, and we are unable to turn off that power supply. The rest are 3.3V.

  • Yasukawa-san,

    Ensure that the PDN is pulled low before removing power here. I believe that the only VDDO that needs to be concerned with in this specific case is VDDO_01 (as it impacts the power on reset circuitry).

    Is VDDO_01 connected to the same 3.3V as VDD_IN/VDD_PLL1/VDD_PLL2/VDD_DIG? If so, then this should not be an issue. If using GPIO to control the PDN pin, pull PDN low, cycle the 3.3V supply, then pull PDN high. Otherwise, cycle the 3.3V supply. An external capacitor can be used to delay PDN = 1.2V until after VDD_IN/VDD_PLL1/VDD_PLL2/VDD_DIG reach 2.72V.



  • Hi Kadeem.

    Thanks for your instant reply.

    VDDO_01 is connected to the same 3.3V as VDD_IN/VDD_PLL1/VDD_PLL2/VDD_DIG, so I am relieved that there seems to be no problem.
    Since we have an external capacitor connected to PDN, we will make sure that PDN is pulled low before turning off the power as you suggested.

    Thank you so much!