BMD-300 EvK with ublox BMD-360 module and nRF52811 power off consumption higher than expected

Hello I'm trying to get the lower consumption with this EvK in power off mode. I was expecting around 0.5uA but the minimum I get is 1.8uA ~ 2uA.

The measure has been done with a nRF Power Profiler and an SMU Keithley 2450.

I've used the "ram_retention" example. (nRF5_SDK_17.1.0_ddde560) but modifying the main function to go directly to power off mode:

int main(void)
{
    bsp_board_init(BSP_INIT_LEDS);

    bsp_board_led_on(READY_PIN_NUMBER);
    nrf_delay_ms(1000);
    
    // Enter System OFF and wait for wake up from GPIO detect signal.
    NRF_POWER->SYSTEMOFF = 0x1;
    // Use data synchronization barrier and a delay to ensure that no failure
    // indication occurs before System OFF is actually entered.
    __DSB();
    __NOP();

    // This code will only be reached if System OFF did not work and will trigger a hard-fault which will
    // be handled in HardFault_Handler(). If wake the up condition is already active while System OFF is triggered,
    // then the system will go to System OFF and wake up immediately with a System RESET.
    display_failure();
}

I've tested using Keil uVision, without softdevice using these ROM, RAM addresses and directives :

  • IROM1: Start: 0x0 / Size: 0x30000  //  IRAM1: Start: 0x20000000 / Size: 0x6000
  • BOARD_PCA10040 BSP_DEFINES_ONLY CONFIG_GPIO_AS_PINRESET FLOAT_ABI_SOFT NRF52 NRF52811_XXAA NRF52_PAN_74 __HEAP_SIZE=8192 __STACK_SIZE=8192
  •  --cpreproc_opts=-DBOARD_PCA10040,-DBSP_DEFINES_ONLY,-DCONFIG_GPIO_AS_PINRESET,-DFLOAT_ABI_SOFT,-DNRF52,-DNRF52811_XXAA,-DNRF52_PAN_74,-D__HEAP_SIZE=8192,-D__STACK_SIZE=8192

I've also tested with a softdevice (s112 - 7.2.0) using these ROM, RAM addresses and directives :

  • IROM1: Start: 0x19000 / Size: 0x17000 //  IRAM1: Start: 0x20001A50 / Size: 0x45B0
  • BOARD_PCA10040 BSP_DEFINES_ONLY CONFIG_GPIO_AS_PINRESET FLOAT_ABI_SOFT NRF52 NRF52811_XXAA NRF52_PAN_74 NRF_SD_BLE_API_VERSION=7 S112 SOFTDEVICE_PRESENT __HEAP_SIZE=2048 __STACK_SIZE=2048
  •  --cpreproc_opts=-DBOARD_PCA10040,-DBSP_DEFINES_ONLY,-DCONFIG_GPIO_AS_PINRESET,-DFLOAT_ABI_SOFT,-DNRF52,-DNRF52811_XXAA,-DNRF52_PAN_74,-D__HEAP_SIZE=2048,-D__STACK_SIZE=2048

Here some screenshots from the Power Profiler Kit:

  

Thanks in advance Slight smile

Parents Reply Children
  • Hi again Jared,

    BTW we have now received our board and the problem is somehow different on this one:

    • u-blox BMD-360 EVK: the leakage is ~5 µA whatever the power supply voltage (tested at 1.8V and 3.0V)

    • On our PCb the leakage is ~8µA at 1.8V and ~16µA at 3.0V, which make me think of a resistive leakage of ~250 kOhm, but I disconnected every connections between the BMD-360 module and the rest of the board. The module power supply is also isolated from the rest of the board

    The further I get, the more confused I am ;)

    Does that remind you of something you know ?

    Thanks in advance.

    Best regards

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