High power consumption on SYSTEM OFF -nrf52820

[Damezumari]

Hi,

GOAL : I try to measure the current consumption in system off only.

PROBLEM : I measure a current of 8uA in system off while in the datasheet of the PAN1781 et nrf52820 it is sub uA with no ram retention.

HARDWARE: I am using a PAN1781 (nrf52820) with the dev board from panasonic ENW89857AXKF.

SOFTWARE: I started using the bluetooth/peripheral_lbs exemple that i modified with the following code. 

void main(void)
{
  NRF_POWER->SYSTEMOFF = 1;
  for(;;){}
}

I tried to desactivate the peripherals in zephyr:

# Drivers and peripherals
CONFIG_I2C=n
CONFIG_WATCHDOG=n
CONFIG_GPIO=n
CONFIG_PINMUX=n
CONFIG_SPI=n
CONFIG_SERIAL=n

How to reduce the consumption to sub uA ? 

Thanks for your help.

[Damezumari]

I have removed a leaking diode, on the dev board and it solved the problem.

I can now observe 300nA to 500nA !

The diode is the shottky D8 RB168VYM-30FH 

mediap.industry.panasonic.eu/.../PAN1781 EVB Schematics.pdf