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Adverting event, current is big

  Dear all  
          I use QFAB QFN48 schematic with internal LDO setup,but my board have not 32.768KHZ.

the Pre_processing current is big when in adverting .Why? image description image description

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  • I expect this to be a short current spike of few us when internal regulators and internal circuitry power ON. This should easily be handled by adding 1uF to 4.7uF decoupling capacitor on VDD, the current may be high, but the time is very short. For instance the 47nF capacitor on DEC2 needs to be charged when powering ON, so you need some decoupling on VDD to handle this. If that doesn't work, please share the schematic so we can take a closer look.

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  • I expect this to be a short current spike of few us when internal regulators and internal circuitry power ON. This should easily be handled by adding 1uF to 4.7uF decoupling capacitor on VDD, the current may be high, but the time is very short. For instance the 47nF capacitor on DEC2 needs to be charged when powering ON, so you need some decoupling on VDD to handle this. If that doesn't work, please share the schematic so we can take a closer look.

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