Current wave in system OFF

[Pepam]

Hello,

I am testing current consumption of my custom board with PPK. There are some passive components (resistors, mlcc) on the board also with active components (accel, adc, gyro, dcdc conv.), which I put to sleep before going to system OFF. System OFF current of my board should be < 17uA theoretically. I am able to achieve this number, but about 15s after nRF52832 entered system OFF. It looks like some gpio capacitance, or some mlcc on board? Did someone encountered similar problem? I have added .ppk file with this behauviour. 

Thank you,

Pepam

ppk_log.zip

[Stian Røed Hafskjold]

Hi, this waveform looks like a floating GPIO (input GPIO with input buffer connected, e.g. MISO, interrupt pin from accelerometer, UART RX, etc.) on the nRF52832. Did you configure any of the pins as an input, while the input level is not defined by the external component, i.e. driven high or low? Maybe there should be a pullup/down resistor on one of these GPIO inputs, to define the level when it's not driven by the slave?

It could also be a symptom of not connecting the GND between the PPK and the DUT when in ampere meter mode. In ampere meter mode you need to connect 3 wires. VIN, VOUT and GND.

Best regards,
Stian