High Current Consumption in nRF5340 in sleep mode

Hi all,

We are working on a project that uses the nRF5340 and nRF7002 combo. In our application, the device enters a low-power mode on the nRF5340 during sleep, with the nRF7002 turned off.

We followed the low-power example code, but we're seeing a high current draw of 3 mA on the nRF5340 alone on our custom board. When we tested the same example on the nRF7002 DK and measured the current at P22, we observed only 14 µA.

Our custom board design follows the nRF7002 DK as reference and we've even removed extra pull-ups and pull-downs, but the current remains the same. Interestingly, when we run the example SYSTEM OFF mode code on the same custom board, we observe a current draw of 5 µA by nRF5340, whereas the DK consumes only 1 µA. This difference can be accepted due to some design/parts.

The main difference between the DK and our design is the operating voltage: the DK uses 1.8V, while our custom board uses 3.3V. While some variation due to this voltage difference is expected, a 3 mA difference seems excessive.

  • Are there any code changes needed for the 3.3V voltage rail?
  • What are the other steps can be taken from our side to reduce the sleep current?

Thanks,

Jagan K

Parents Reply
  • Hi Hakon,

    #1. In 3.3V rail, nrf7002 worked under QSPI, so we haven't done any change, but we are discussing & planning for the 1.8V power rail change.

    #2. In system OFF case, there is no issue with the current consumption and we have verified that.
    But when we try to put the device in low power mode, the current consumption is high that nrf5340 chip alone takes 3.2mA. In this state, power supply for nRf7002 is turned OFF.

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