Cant reach nRF52840 PS specified current consumption in system off mode

[Sridhar Jonnavittula]

Hi all,

I am using power profiler kit to measure as mentioned below screenshot. 

I want to achieve current number as mentioned in Nordic product specification as" IOFF_RAMOFF_RESET System OFF, no RAM retention, wake on reset 0.40 μA"

I think I must do these for low power and modified code add DCDC function, set noram retention, set lfclock. I modified the code in ble_power_profiling as follows:

---------------------------------------------------------------------------------------------------------

power_management_init();

ble_stack_init();
sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);

if (!m_is_notification_mode && !m_is_non_connectable_mode)
{
// The startup was not because of button presses. This is the first start.
// Go into System-Off mode. Button presses will wake the chip up.
nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);
}

------------------------------------------------------------------------------------------------------------

I am not achieving the number in spec. So please suggest me what I am missing.

Thanks,

Sridhar

[Stian Røed Hafskjold]

Unfortunately, the accuracy of the PPK is not that great. I think 0.57µA is a pretty good result. It's in the ballpark considering the PPK accuracy and the chip to chip variation.