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TPS65217CEVM: LM5576: The PB_IN pin connection of TPS65217C

Jimmy Zhou95
Intellectual 870 points
Part Number: TPS65217CEVM
Other Parts Discussed in Thread: LM5576

In the datasheet, the PB_IN pin is connected to 5V internally and can be connected to GND externally with LOW level enabling.
However, when I use TPS65217C, some TPS65217C can work with PB_IN float and some TPS65127C can work with PB_IN connected to GND.
So what is the correct method to handle the PB_IN pin? Is it proper to connected to high level or GND by a specific resistor?

  • 0
    TI__Genius 17380 points
    Hi Jimmy,

    Section 8.3.3 Push-Button Monitor (PB_IN) in the datasheet has more information on the pushbutton detection.

    If there is a push button in the customer circuit, the push button should connect the PB_IN to GND. If they do not have a push button in their design, it depends how they power the system. Figure 24 (Global State Diagram) shows the possible power on scenarios. From the OFF state, USB or AC detection can cause a power on, so if they are used then PB_IN can be floating. If a start-up condition is needed without USB or AC being plugged in, then a falling edge on PB_IN needs to be generated.

    As noted in the upper right corner of Figure 24, if PB_IN is tied to GND, then after 8 s the device will reset (long key press, similar to a phone / smart watch / etc).

    Let us know if there are more questions on its operation, or if it has any relation to the LM5576 listed in the title of the question.