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Original question:

TPS7A03: Leakage current when Vin < Ven

TPS7A03: Operation when VIN < VEN

Taito Takemura
Intellectual 2310 points
Part Number: TPS7A03
Other Parts Discussed in Thread: TLV755P

Hi experts,

I believe that VIN < VEN may occur in the application of my customer's product under development. Could you please answer the following questions about the TPS7A03 behavior when VIN<VEN?

- Is it correct to understand that "In the situation of VIN<VEN (eg VIN=0V, VEN=3.0V), the consumption current increases, but it does not affect the reliability or damage of the product". 

The customer thinks as above from the fact that the absolute maximum ratings of Vin and Ven are stipulated independently, and from the behavior of other LDOs such as TLV755P. TLV755P datasheet 7.3.2 clearly states that VEN current increases when VIN<VEN suggesting that there is no problem in use if the user can tolerate an increase in the current of VEN. Is it the same for TPS7A03?

Thank you for your help.

Regards,

Taito Takemura

  • 0
    TI__Mastermind 33965 points

    Hi Taito,

    If Vin = 0 and Ven = 3V, then the device will operate in shutdown.  This is because the input voltage will not be sufficiently high to trip the UVLO threshold.  The expected current would be the EN pin leakage current, possibly 10nA as listed in the datasheet table.  Keep in mind that your input capacitor may leak more than this, especially if the PCB has had rework completed.

    An example where the Iq was measured for the TPS7A03 when Vin = 0V and Ven = 1.1V is provided in figure 6-9 in the datasheet.  1.1V is the minimum EN threshold to turn the device on.

    Thanks,

    Stephen

  • 0 in reply to Stephen Ziel
    TI__Intellectual 2310 points

    Hi Stephen,

    Thank you for your answers. Could you please tell me the additional questions?

    Thank you for your help

  • 0 in reply to Taito Takemura
    TI__Intellectual 2310 points

    [Questions]

    (Q1) What is the EN pin leakage current when VIN=0V and EN pin >1.1V?  There is no problem if you know that it will not be larger than 10nA.

    (Q2) Since the absolute maximum ratings for VIN and VEN are specified independently for this product (see diagram below).
    Am I correct in understanding that even when VIN=0V and VEN=3.0V, the reliability of the product is not affected (of course it shuts down)?

  • 0 in reply to Taito Takemura
    TI__Mastermind 33965 points

    Hi Taito,

    For Q1, I'm not expecting anything larger than 10nA.  If you have a capacitor on the EN pin then I expect the leakage of the capacitor to possibly dominate.

    For Q2, your understanding is correct and the reliability of the device is not affected with these conditions.

    Thanks,

    Stephen