nrf52 high current after sd_power_system_off

[yaron]

Hi I am trying to put the nrf52 device to system off state, in order to get minimal current consumption. When I don't use the soft device, and enter system off state by "NRF_POWER->SYSTEMOFF = 1", I see that CPU current goes down to a few uA. But when I enable the softdevice (using "SOFTDEVICE_HANDLER_INIT"), and than enter system off state by ""softdevice_handler_sd_disable" & "sd_power_system_off", I see CPU current of 5.83 mA!!!. If I add "NRF_POWER->SYSTEMOFF = 1" after "sd_power_system_off" , the CPU current goes down to 2.46 mA. I am currently using soft device version s132_nrf52_1.0.0-3.alpha. Is this a known issue with this version? If not, can some please explain? What is the correct way to enter system off state after soft device is enabled?

Thanks Yaron

[Stefan Birnir Sverrisson]

Ok, then your anomaly is not present and you should be measuring normal current consumption. I have measured now with the PCA10040 (contains Eng B QFAABA), s132_nrf52_2.0.0-7.alpha_softdevice, and the ble_app_template example from nRF5 SDK 11.0.0-2.alpha. I measure around 1uA when the nRF52 enters System Off mode. When advertising, I measure 100uA - 150uA, not very stable reading with a 300ms advertising interval. If I change the advertising interval to 100ms, then I measure around 350uA average current consumption.

What measuring method are you using? Are you following the methods described here?

Are you measuring the same current consumption on both preview nRF52-DK and your custom board? If so, then it is hard to conclude that it is a hardware problem.

Make sure you power reset the board after flashing your code to the chip.

What happens if you run the blinky example and measure current consumption on that?