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TPS7A7300 EN pin

Martin Dusek
Intellectual 340 points
Other Parts Discussed in Thread: TPS7A7300

Hello, is it possible to drive EN pin of TPS7A7300 with slowly changing signal (1V/s) or should we use Schmitt trigger? We need to switch TPS7A7300 on 2 s after input voltage stabilizes.

  • 0
    TI__Guru 55940 points

    Hi Martin,

    A slow charge on the enable pin would leave the signal in the hysteresis area for a long time.  This could lead to unpredictable responses in your system.  Have you considered using something like the TPS3808G01 to do your delay?  This is a low power supervisor that you could program for the 2 second delay and would allow for a faster enable signal.  If you have other sequencing needs in your system you could look at dual and quad packages.

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Intellectual 340 points

    Dear Ryan,

    thanks for your response. We'll use RC network together with Schmitt buffer.

     

    Best regards

     

    Martin

  • 0 in reply to Martin Dusek
    Intellectual 340 points

    Hello,

    I have another question about LDO TPS7A7300 and its pin configurable voltage.

    http://www.ti.com/product/tps7a7300

    IC has adjustable output voltage with:

    - external resistor divider from 0.9V .. 5V or

    - voltage settings pins 0.9V .. 3.5V

    but we need output voltage 3,65V. It's possible to set it with voltage divider, but it needs >E24 resistor or combination from lower E's

    In datasheet @ page 15 is note:

    -----------------------------------------------------------------------------------------

    Any output voltage setting that is not listed in Table 1 is not covered in the Electrical Characteristics. For output voltages greater than 3.5 V, use a traditional adjustable configuration (see the TRADITIONAL ADJUSTABLE CONFIGURATION section).

    -----------------------------------------------------------------------------------------

    I connected all settings pins to GND for output voltage 3,65V and I haven't discovered any problems. Why should we use external voltage divider for the output voltage greater than 3,5V?

    And another question: Is it possible to combine Traditional adjustable configuration and User Configurable Output Voltage Setting (eg. coarse setting by E12 external resistors and fine setting by connecting pins of LDO to GND)?

  • 0 in reply to Martin Dusek
    TI__Guru 55940 points

    Hi Martin,

    It is possible to combine the traditional adjustable configuration (resistor divider) with the user configurable output voltage setting for this part.

    The Electrical Characteristics in the datasheet were written for a maximum user configurable output voltage 3.5V.  If you choose to configure the device for 3.65 using the user configurable output method, it is outside the parameters of the datasheet.  The device may work under such a configuration, but we do not cover the such usage in the datasheet.

    Very Respectfully,

    Ryan