Is there any problem in current consumption of nRF52-DK when SB9 is not opened ?

[Daewoong Kim]

Hi Experts!

I read some posts related to current measurement, and i have a question.

if SB9 is not opened, current consumption is increased??

i have a Source Measurement Unit (SMU), manufactured by (NI)National Instruments (NI PXIe-4139, NI PXIe-1078),

so i measured current consumption by applying power to Extneral supply port (P21) on nRF52-DK.

However, the measured idle current is about 160~170uA between advertising events.

Of course i used "sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE)" and "sd_app_evt_wait()" functions.

Also, I disabled NRF_LOG_ENABLED, NRF_LOG_BACKEND_SERIAL_USES_UART, and just advertising operation

conducted without any other operation.

Anyway...

At least, i want to know about whether the cause of idle current of 160~170uA  is SB9 shorted or not ..!

please answer..!

- Daewoong Kim

[Stian Røed Hafskjold]

When you measure current going into P21, you will power all the other components on the board as well, including the Segger chip (debugger), this will consume a lot of current. To isolate the nRF52 from the rest of the board, only measuring the nRF52 current, cut SB9 and measure current going though P22.

[Daewoong Kim]

When i use multi-meter to measure current after cutting SB9, current consumption is remarkably dropped, and IDLE current is observed about 2~3uA !