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Original question:

LM2759: current accuracy, external components , sequence

LM2759: Current sink accuracy

Yanni Li
Intellectual 1960 points
Part Number: LM2759

Hi,team

My customer has a question.

The LED current sink accuracy is only specified at 220mA flash mode in the datasheet.

Could you please tell the accuracy for torch mode 15mA?

Thank you.

  • 0
    TI__Mastermind 22745 points

    Hi Yanni,

         I'm sorry that we don't have such kind of data on hand, and it is supposed <+/- 30% for torch mode 15mA.

    BR

    Sean

  • 0 in reply to Sean Zhou
    TI__Intellectual 1960 points

    Hi Sean

    Thank you for your reply.

    My customer made about 100 devices incorporating the LM2759SD.
    The device operates in torch mode 15mA, Flash mode 150mA and 280mA.
    In Flash mode 150mA and 280mA, the current error is within ± 10%.
    But with the two devices, the current in torch mode 15mA was 6.7mA and 8.3mA.
    Do you think these two LM2759s are normal or damaged?

    Condition: One LED is connected to the LM2759DS. Vin of LM2759 is about 3.8V. Vf of LED is about 2.6V at If 15mA .

    Regards,

    Jenny

  • 0 in reply to Yanni Li
    TI__Mastermind 22745 points

    Hi Jenny,

        Thanks for the detail explaination, as you know for such device, we can only guarantee the current accuracy under full scale current and we cant' guarantee the current accuracy for the whole current range.

    BR

    Sean