Regrading Sleep current in nrf52840

Hi Team,

we have one doubt regarding sleep current when we try to measure with power analyzer(nrf52840 EVM Board) .we got 5.23 micro amps instead of 2.35 micro amps.

we used this example code D:\santhosh\Penny\nrf52840\nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\ram_retention for current measurement can you help regarding this so it will be so helpful for our team

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  • Hello Santhosh,

    You can measure current in two ways, either using source meter mode or ampere meter mode (Nordic Semiconductor Infocenter). The problem with the source meter mode is that you have to make sure that you are not powering the rest of the board ( debugger chip etc) with the Power profiler kit (PPK). The problem with ampere mode is that there is noise on the current measuring header which leads to 5-10 uA current leakage. 

    You can find a switch (SW10) on the PCA10056 where you can choose to supply nRF52 directly using the supply header. This switch is called VEXT-> nRF.  So if you now connect the PPK to the external supply header, flip this switch, and leave the USB connected to power the rest of the board, you should be powering the nRF52 from the PPK. You also have to turn the switch (SW6) to nRF Only from DEFAULT to avoid the leakage current. Also remember to reset the board or power on and off after flashing. 

      

    Could you please try this first and see what will be the current afterwards? 

    BR

    Kazi Afroza Sultana

  • hi Kazi,

    Our team went into what you said. But we don't have PPK kit for current measurement then what to do if we want to measure the sleep current?

    Same method we followed for the CPU running 

    ICPU0 CPU running CoreMark @64 MHz from flash, Clock = HFXO,Regulator = DC/DC   --> 3.3 mA

    we got 3.3mA what is in the datasheet without PPK Kit By using this example code

    nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\flashwrite

    Now for sleep current we are following this example code 

    nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\ram_retention

    IOFF_RAMON_RESET System OFF, full 256 kB RAM retention, wake on reset 1.86 μA 

    But we are getting what is given in the datasheet

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  • hi Kazi,

    Our team went into what you said. But we don't have PPK kit for current measurement then what to do if we want to measure the sleep current?

    Same method we followed for the CPU running 

    ICPU0 CPU running CoreMark @64 MHz from flash, Clock = HFXO,Regulator = DC/DC   --> 3.3 mA

    we got 3.3mA what is in the datasheet without PPK Kit By using this example code

    nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\flashwrite

    Now for sleep current we are following this example code 

    nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\ram_retention

    IOFF_RAMON_RESET System OFF, full 256 kB RAM retention, wake on reset 1.86 μA 

    But we are getting what is given in the datasheet

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