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TPS53119: Power Good (PGOOD) Indicator Voltage Low

Part Number: TPS53119


I am having trouble getting the expected voltage from the PGOOD pin when the TPS53119 is done starting up.

Below is a screenshot of part of my schematic:

R52 sets the soft-start time, along with R47 I am expecting PGOOD to have a voltage of 5V once the supply is done starting, but I am getting 62 mV instead from PGOOD_3V3.

Thanks in advance.


Chris W.


    I am sorry that you are having difficulty with the PGOOD on the TPS53119.  The PGOOD on the TPS53119 is an Open-Drain pull-down that drives the PGOOD voltage low when the FB voltage (Pin 3) is outside of the specified range around the regulation voltage.  There is also a 1ms release delay, so if there is excessive ripple on FB, either due to noise or RCC ripple injection from a compensation circuit added across the inductor, it can cause the PGOOD pin to remain low.

    You schematic does not show what the inductor, output capacitor or feedback network look like, so I can't evaluate if there might be excessive ripple on FB causing FB to be held low, so let's try a couple of things:

    1) Check the soldering of R47 first to make sure there is a pull-up on PGOOD, without an external pull-up, PGOOD will remain low.

    2) Check FB with an oscilloscope to verify it's level and AC ripple.  When PGOOD is low, a FB voltage of greater than 648mV could trigger the upper threshold of PGOOD and prevent PGOOD from being released.

    3) Review any components that might be injecting additional ripple voltage into FB, especially an RC across the inductor, capacitively coupled into the FB pin, which may be injecting more than 50mV peak to peak ripple on FB.

  • After double checking my design, I realized I had another potential divider down the line. I removed it and it solved the issue

    Sorry, it was a non-issue. I appreciate you following up.

    Thank you so much.