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LP5907: alternate device for LP5907 (reduce inrush current during turned on)

Yasushi Fujiwara
Genius 12725 points
Part Number: LP5907

Hi Team,

My customer is facing a same situation as below thread. I think it is not unusual behavior of LP5907. But customer wants to know how to reduce the inrush current. Do you have any idea? Also do you have a alternate device which is same as low cost and small package? Customer mentioned this device is very good device except this inrush current.

https://e2e.ti.com/support/power-management/f/196/t/672133?tisearch=e2e-sitesearch&keymatch=LP5907%20inrush

Best Regards,
Fujiwara

  • 0
    TI__Guru 55940 points
    Hi Fujiwara,

    You are correct that inrush current is considered normal for LDOs. This is the additional current to charge the output capacitor at startup. It is important to note that this high current is flowing into the output capacitors and not flowing into the load. Since the inrush current is used to charge the output capacitors, you can reduce the inrush current by reducing the output capacitor values.

    If the concern is that the inrush current is collapsing the input power rail, additional input capacitance can be added. This additional capacitance will help source the inrush current when the LP5907 is enabled.

    Unfortunately LP5907 does not have a soft-start function which can help limit inrush current by slowing the rise of the internal bandgap due to its pinout.

    Very Respectfully,
    Ryan