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TPS3828 pinout in datasheet does not match pin function table

Naji Naufel
Intellectual 805 points
Other Parts Discussed in Thread: TPS3828, TPS3824, TPS3825, TPS754

Hi,

I need a supervisory device to drive the active-low enable of the TPS75433 LDO to hold it inactive until the upstream 5V rail has come up.

The TPS3828 looks like it would work but the datasheet has conflicting information.

The Device Comparison Table shows the TPS3828 as having a RESET and /RESET pins where the RESET pin is open-drain.

However, the pin Configuration diagrams show it as having ONLY /RESET pin.

Which of these devices has the open-drain RESET pin?

Can I get a device that comes up with open-drain output and drives LOW after the VDD threshold and time out period have been satisfied?

  • 0
    TI__Guru 55940 points
    Hi Naji,

    TPS3824 and TPS3825 have RESET pins; however, neither are open-drain. TPS3828 is the only device in the family with an open-drain output.

    Could you help me understand the desire for an open-drain output rather than a push-pull output?

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    Intellectual 805 points
    Hi Ryan,

    The TPS75433 LDO has an active-low EN pin. I like to keep it disabled until the upstream 5V Buck has come up. I was told that floating the EN keeps it in disable state.
    So, If I use the TPS3824 with the push-pull RESET pin, I should be good?

    Thank you
  • 0 in reply to Naji Naufel
    TI__Guru 55940 points
    Hi Naji,

    As you state, the TPS754 output is enabled when EN is pulled to logic low. The output is disabled when EN is pulled to a logic high. The push-pull RESET of either TPS3824 or TPS3825 will be pulled to a logic high (the value the supervisor's VDD) until VDD crosses the threshold. At this time, RESET will transition from logic high (disabling TPS754) to logic low (enabling TPS754).

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    Intellectual 805 points

    Thank you for the confirmation. I will use the TPS3824-33.

    Do you agree that the table describing the pin functionality above the pinout diagrams is wrong for the TPS3828 and needs correcting?

  • 0 in reply to Naji Naufel
    TI__Guru 71516 points

    I agree that the chart and the pinout is confusing.  There is a Submit Documentation Feedback  link at the bottom of each datasheet page, and I encourage you to report this using that link.

    ~Leonard