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TPS3898P

Hi,

I would like to know the range of delay tpd(r) that i can get from this IC by means of adjusting the capacitor CT.

Can someone clarify on this one?

  • Hi Vasanthan,

    You can calculate this from the charging pin current range and a few other factors.


    We actually have a calculator for this one that we made for another customer question:

    4540.TPS3896 Timing calculator.xlsx

    Regards,

    David

  • Hi David,

    Thank you for your reply and the excel sheet that you shared.

    Actually, I would like to know what is the maximum delay this IC can offer?

    i.e. Can i get the delay upto 5 Sec to 10 Sec by having corresponding capacitor?

     

    Thanks,

    Vasanthan N

  • Hi Vasanthan,

    The maximum delay time is constrained by the leakage current through the Ct capacitor. As the capacitance value gets larger, the leakage current generally increases. At a certain point the leakage current through the device is not able charge Ct to the needed voltage.

    This device is easily capable of doing a 5-10 second delay time, and the scope shot below shows a test I ran a while back with a 6.8uF capacitor to give a 30 second delay time. The device was a TPS3897A, Channel 1 (yellow) is SENSE and channel 2 is RESET (pink).

    Regards,

    David