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TPS7A24: How to know Startup time / Soft start

teritama
Expert 1965 points
Part Number: TPS7A24

Hi team,

Our customer want to know information of  startup time in this device.

It is necessary that startup time is more than 33us because of power up slew rate requirement in load side.

Do you have some information about startup time in this device?

If there are no information, Could you recommend me other device that is equivalent price?

Best regards,

teritama

  • 0
    Expert 1965 points

    Hi team,

    I need your information in order to make report.

    Could you let us have your answer by this week?

    If you're not clear about anything, please tell me.

    Best regards,

    teritama

  • 0
    TI__Mastermind 18466 points

    Hey Teritama, 

    It seems as if my reply never posted, 

    But there are many things that influence Start-up time - temperature, load, slew rate, enable etc. 

    I do have scope shots of this device performing with a start-up ranging from 500us to 1.4ms, so it is definitely possible to have a start-up time greater than 33us.

    Best,

    Juliette

  • 0 in reply to Juliette
    Expert 1965 points

    Hi Juliette, 

    Thank you for your reply.

    I understood that start-up time will be 500us to 1.4ms.

    Is there a way to roughly guess start-up time?

    Or could you introduce me the device can be used in following condition and be specified start-up time?

    Vin:12V

    Vout:3.3V

    Iout:100mA

    Best regards,

    teritama

     

  • 0 in reply to teritama
    TI__Mastermind 18466 points

    Hi Teritama, 

    I can do a cadence simulation. What capacitors would you be using [Cin, Cout, Cff]?

    Best,

    Juliette

  • 0 in reply to Juliette
    Expert 1965 points

    Hi Juliette,

    I will use TPS7A2433, so not use Cff.

    Cin=1uF, Cout=2.2uF

    Best regards,

    teritama

  • 0 in reply to teritama
    TI__Mastermind 18466 points

    Hi Teritama,

    I will reply with a simulation model as soon as the designer sends it to me.

    Best,

    Juliette

  • 0 in reply to Juliette
    TI__Mastermind 18466 points

    Hi Teritama,

    Below is the snapshot of the startup behavior with the conditions that you mentioned :

    Cout = 2.2uF, Vin = 12V, Vout = 3.3V, Iload = 100mA

    The one in green is with VIN & EN tied together and the one in red is with EN coming up separately at 300us.

    For both the cases, startup time is around 51us (measured from 10% to 90% of Vout).

    Best, 

    Juliette