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TPS40303: BP VDD 5V

Mark Ackerson
Genius 10190 points
Part Number: TPS40303
Other Parts Discussed in Thread: TPS40304, TPS40305

Can customer connect TPS40303 BP to VDD=5V?  The reason for the unusual request is we are trying to replace a competitors device in an existing application.

Regards,
Mark

  • 0
    TI__Guru 51555 points

     

    Yes, BP can be connected to VDD with the following limitations

    1) BP should never be forced higher than VDD by more than 0.3V to avoid forward biasing a parasitic diode through the VDD to BP LDO

    2) BP should never be forced higher than its absolute maximum voltage of 7V

    In general, I would recommend including a 10 microsecond or greater filter between the Power Stage input and the BP regulator, which powers the analog circuitry of the TPS40303 controller and could be negatively impacted by the AC ripple on the power-stage input.  To maximize the gate drive voltage, I would recommend a 1-Ohm resistor and 10uF bypass capacitor.

    If these are not in place in the existing application, they are not critically needed, but a large AC ripple on BP may impact performance.

  • 0 in reply to Peter James Miller
    TI__Prodigy 55 points

    The schematics for this part show a 10-100K resistor placed on the Power Good output. If we’re not planning on using the PGood pin is it still recommended to have this external resistor connected or would we be fine without it?

  • 0 in reply to Corbett Kaniff
    TI__Expert 4795 points

    Hi,

    Peter will feedback to you next week.

  • 0 in reply to Corbett Kaniff
    TI__Guru 51555 points

     

    Asking new, unrelated questions within an existing Engineer to Engineer thread make searching for questions and existing answers extremely difficult.  In the future, please submit a new E2E thread with a new question rather than replying to an existing thread.

    That said,

    The PGOOD on the TPS40303, TPS40304, and TPS40305 devices are open-drain pull-down outputs and the PGOOD voltage is not used for any internal function.  If not used, PGOOD can be safely shorted to GND or left floating.

  • 0 in reply to Peter James Miller
    TI__Genius 10190 points

    Thanks for the support Peter!

    Regards,
    Mark