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Peak current when BLE-TX/RX and CPU run simultaneously

Hi!

My question is for the purpose of power calculations for both the nRF52832 and nRF52840 for BLE use only.

I haven't been able to find a reference for this.

I see that the current requirement for the CPU is ~7mA and the BLE TX is at 8.7mA (from memory).

Do these devices TX or RX while the CPU is running, so that the peak current is around ~15mA?

We want to see what to expect when a CR2032 reaches low voltage and the internal resistance gets high. We are concerned about the brown-out-detector getting triggered at these levels and need to know the lowest possible voltage that we can run with on the battery!

Are these two events serialized by the hardware (is the CPU halted when TX or RX) ?

Thanks.

Parents
  • Do these devices TX or RX while the CPU is running,

    Yes. You need to account for the possibility that the CPU is running while the radio is also active. But make sure you read up on the electrical specs and different ways of optimizing power. If you chose to utilize the internal DCDC regulator and TX at 0 dBm then you are looking at these values:

    IRX,1M,DCDC

    RX only run current (DCDC, 3V) 1Msps / 1Msps BLE

            5.4  

    mA

    ITX,0dBM,DCDC

    TX only run current (DCDC, 3V)PRF = 0dBm

            5.3   mA
    IDDFLASHCACHEDCDC

    CPU current, running from flash, cache enabled, DCDC 3V

            3.7   mA

    Worst case is 9.1 mA with RX and CPU only concurrently.

Reply
  • Do these devices TX or RX while the CPU is running,

    Yes. You need to account for the possibility that the CPU is running while the radio is also active. But make sure you read up on the electrical specs and different ways of optimizing power. If you chose to utilize the internal DCDC regulator and TX at 0 dBm then you are looking at these values:

    IRX,1M,DCDC

    RX only run current (DCDC, 3V) 1Msps / 1Msps BLE

            5.4  

    mA

    ITX,0dBM,DCDC

    TX only run current (DCDC, 3V)PRF = 0dBm

            5.3   mA
    IDDFLASHCACHEDCDC

    CPU current, running from flash, cache enabled, DCDC 3V

            3.7   mA

    Worst case is 9.1 mA with RX and CPU only concurrently.

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