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TPS7H2201-SP: Is OFF time related to Css

Part Number: TPS7H2201-SP

Hi Team,

We have received an inquiry from our customer as follows.

I have some questions about TPS7H2201-SP.
(1)According to the data sheet, the OFF time of the current when turning off at the time of hard short is 61us in TYP when Css=2.7nF, but is the OFF time related to Css?
(2)Similarly for soft shorts, Vout Fall Time is 90nses when Css=1000pF. Is Vout Fall Time related to Css?
(3)Is it possible to set the Current Limit even with several tens of mA.

Thank you in advance for your response.



  • Hi Danilo,

    I'm researching your questions and will get back to you soon. 

    For your 3rd question, are you asking if the current limit can be set to very low values (10s mA)?



  • Hi Danilo,

    Thanks for waiting. Here is what I was able to find out:

    1. Yes, if CSS is large enough it may extend how long the device remains off when it is disabled after a hard short. Part of the off time is due to internal circuit delays, but if CSS is large enough then it will take longer for the SS charge current to charge the capacitor and allow the FET to start turning on.
    2. The Vout Fall Time (tF)  parameter is not related to CSS. This parameter is meant to specify the amount time it takes Vout to drop from 90% to 10% of its full value after the EN signal goes low (this is shown in Figure 19 in the datasheet), which will mainly depend on the R and C values on the output.
    3. If I understand correctly, you are asking if it is ok to set the current limit to very low values. If the load is 1A or less, the lowest the current limit can be set is Iout+0.5A.

    Hope this helps!



  • I am grateful for your kind reply.
    Also, I'm sorry for the late replay.
    I have a few question about 1.

    1. When a hard short occurs, the fall time time to off is also 2.
       Is it as unrelated to Css as?

    2. I understand

    3. I understand


  • Hi,


    Yes, the fall time of Vout after a hard short occurs will also depend on the R and C values on the output and will not depend on CSS.

    This is true for all three scenarios (hard shorts, soft shorts, and when EN goes low during normal operation), but Vout fall time is only specified in the datasheet for the scenario where EN goes low during normal operation.

    The fall time for soft and hard shorts will depend on the specific conditions of the short. For example, the new R value on the output due to the short & the value Vout dips to before the device shuts off.



  • Thank you very much.

    I understand everythngs.

    Best regards,