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TPS7A4901 cycles on and off

Sunglin Chen
Expert 2335 points
Other Parts Discussed in Thread: TPS7A49

Hi,

I use a TPS7A4901 to design a 24V to 3.3V circuit which was attached. The load was about 120mA. It cycles on and off after 2 or 3 seconds when power on. I would like to know anything wrong with my circuit. Does anyone have the same issue?  How to achieve my requirement that to design a 24V to 3.3V circuit with a maximum load of 150mA.  Thank you.

Sunglin.

  • 0
    TI__Expert 8905 points
    Hi Sunglin,

    It sounds like you are entering thermal shutdown. Using the TPS7A49 in the conditions described, you are dissipating ~2.5W across the device, which comes out to a temperature rise of ~160C worst case - this will cause the part to shut itself down to prevent damage to the IC.

    I would advise a buck converter and post-regulate the buck converter with an LDO if needed.

    Regards,
    David
  • 0 in reply to David Hopkins
    Expert 2335 points
    Hi David,

    Yes, you are right. The thermal pad is very hot and it did enter thermal protecting mode. I will try to use other components. Thank you.

    Sunglin.