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TPS799-Q1: maximum capacitor

Randy Wang
Intellectual 1705 points
Part Number: TPS799-Q1

Hi Team

  Please help to confirm the maximum capacitor for TPS79933-Q1, in Datasheet it only state the minimum capacitor 2.2uF. thanks.  

  • 0
    TI__Guru 55940 points
    Hi Randy,

    We will respond on the next US Business Day.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Guru 55940 points
    Hi Randy,

    What size capacitor are you planning to use?

    TPS799-Q1 was optimized for an output capacitor of 2.2uF. As such, this particular LDO was tested and characterized with 2.2uF. While larger output capacitors are okay, it is important to keep in mind that with a rated current of 200mA, it may take a long time for TPS799-Q1 to startup with a large capacitor load.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Intellectual 1705 points

    Hi Ryan

      Just want to make sure is that ok to have 4.7uF*3+10uF capacitors? How's the startup time by this output capacitors setting? thanks. 

  • 0 in reply to Randy Wang
    TI__Guru 55940 points
    Hi Randy,

    Yes ~25uF will be okay.

    Startup time depends on several application specific factors such as load current and output voltage . This is due to the standard capacitor charging equations:

    t = (delta V / I) * C

    For TPS799-Q1, it also depends if you are using a fixed voltage version which includes a quick-start circuit or an adjustable version which has no quick-start circuit. Either way startup time will increase as capacitance increases by the amount of time it takes to charge the larger capacitor.

    Very Respectfully,
    Ryan