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TPS65217: What happens when nRESET is low when power is applied?

Part Number: TPS65217

Hi, I am wondering what happens if I have the nRESET pin pulled low and then apply voltage to AC (or USB). Will the chip power up and then go into the reset state?

Can I then be sure that it turns on when I later release the nRESET to a high level?.

I don't think this question has an answer in the datasheet.

Thanks,

  • Hi Daniel,

    If nRESET is held low when supply power is applied and PWR_EN is asserted, the device will start the power up sequence. Immediately following the power up, it will enter the RESET state. The PMIC will remain in the RESET state as long as the nRESET pin is held low (or for a minimum of 1 second). After the nRESET pin is pulled high, the device goes back to the ACTIVE state through the default power-up sequence. This information can be found in Section 8.3.6 of the datasheet and is pictured below.

    Note that the first power up sequence will conclude before the device proceeds to the RESET state so there will be a window of time where the power rails will be enabled even if the nRESET pin is held low when you first apply the system voltage.

    Thanks,

    James

  • Excellent. Thank you.