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TPS62740: Quiscent Current issue

Shankaranarayanan P V
Intellectual 270 points
Part Number: TPS62740

Hi,

   I am using TPS62740 in my product, in which I have pulled up all the VSEL pins to give an output of 3.3v, the IC is working initially, but after the product goes into field testing for few weeks, the IC's quiescent current increases to 1mA. And when it is replaced with a new one, the issue gets solved. This problem has occurred multiple times. I am attaching below the schematic for reference.  

  • 0
    TI__Mastermind 21710 points

    Hi,

    Could you please confirm whether the test conditions were the same in all cases. Also, quiescent current is temperature dependent.

    Secondly, If it was the same, could you please provide the values in each case.

    Regards,

    Febin

  • 0 in reply to Febin
    Intellectual 270 points

    Hi,

      There is just two test case environment right now, one is in the factory and other in the field so. In the factory, the room temperature is around 25-30 degrees celsius and in the field, it may vary from 25-40. While in the factory the quiescent current is around 12uA. After going to the field, this gets varied to 1mA. 

    Regards,

    Shankar 

  • 0 in reply to Shankaranarayanan P V
    TI__Mastermind 21710 points

    Hi,

    Can I please rephrase what I understood. 

    TPS62740 in the factory (25-30 deg cel) has quiescent current around 12uA. When the same device goes into field,  quiescent current goes upto 1mA. So you use the same device multiple times to measure Iq. Is the load the same all the time? Also, you mentioned it gets resolved when you use a new device. What did you mean by this? On the contrary, you mentioned it is occurring many times. So I'm a bit confused here. 

    So, does the replacement device also exhibit the same problem. Like, initially it is fine and then the Iq increases. Did you mean this?

    Regards,

    Febin

  • 0 in reply to Febin
    Intellectual 270 points

    Hi Febin,

          Sorry for not being clear. After assembling the TPS62740 on our board, we test the overall current consumption, so that's when I measured the quiescent current to be 12uA. Since the current seemed to be normal, we sent the board for the field testing. Within a week, the battery got drained out. Now, to find the issue, I checked the current consumption of each IC assembled in the board, that's when I found out that TPS62740 is consuming a current of 1mA. I disconnected all the loads but the current remained the same. And yes, the load is the same all the time. When replaced with a new TPS62740, the current initially is fine and then it increases.

    Regards,

    Shankar

  • 0 in reply to Shankaranarayanan P V
    TI__Mastermind 21710 points

    Hi Shankar,

    Thank you for the details. Could you please specify the exact test conditions used to measure Quiescent current. Please also specify the EN pin status. 

    Regards,

    Febin

  • 0 in reply to Febin
    TI__Mastermind 21710 points

    Hi Shankar,

    I also noticed that the CTRL pin has a 1M resistor. If this pin is unused then I suggest to GND the pin directly.

    Regards,

    Febin

  • 0 in reply to Febin
    TI__Mastermind 21710 points

    Hi Shankar,

    I hope you could solve your issue.

    Due to inactivity I will close this post. Please feel free to re-open if you wish to do so.

    Regards,

    Febin