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LMR51440: LM51440SDRRR

James Calvin
Prodigy 50 points
Part Number: LMR51440

Tool/software:

I am using the two LM51440SDRRR IC.  I have a 12-volt input and a +5Volt and +3.3Volt outputs.  I have included a picture of the schematic.  

We are seeing 1.6mA of current into the circuit when +5Volt is off.  

The data sheet indicates the off current should be 6uA

  • 0
    TI__Mastermind 24115 points

    Hi James,

    I took a look at your schematic and it looks like the EN resistor network on U2 will pull some current. Please remove R5 and enable the device through an external power source as done in U1 to get an accurate assessment on the input current of your application.

    Thank you,

    Joshua Austria

  • 0 in reply to Joshua Austria
    Prodigy 50 points

    Thank you for your response, Joshua.  Sorry for the confusion, but we are measuring the current into U1 with the EN pin pulled low.  I included U2 only because it was on the same page.  With U1 EN pin pulled low, we are seeing 1.6mA of current still going into U1.  

  • 0 in reply to James Calvin
    TI__Mastermind 24115 points

    Hi James,

    Can you please let me know these three things so I can better assist you:

    • Can you confirm that your device is isolated from all downstream components?
    • Can you please share how you are measuring the input current and from what point?
    • Have you done an A-B-A swap and seen significantly different currents with a different device?

    I want to eliminate the possibility that this is a factor of the test setup or the IC.

    Thank you,

    Joshua Austria

  • 0 in reply to Joshua Austria
    TI__Mastermind 24115 points

    Hi James,

    As I have not heard back from you for some time now, I will close this thread. Should you have any new information, please feel free to open the thread and I would be happy to assist you.

    Thank you,

    Joshua Austria