High power consumption on SYSTEM OFF - nRF52810

[chrismoi]

Hello DevZone,

I have made some custom boards with Laird's BL651, wearing nRF52810 chip. I was testing the power consumption and I can't get it down to uA level in system off. 

The board drains 2.5mA minimum when in system off, with a gpio sense input for wake up.

The board consists of a PDM microphone, 2 LEDs and a tactile switch. I checked the voltages from the respective GPIOs while measuring the current, and they were fine. The microphones stays off if there is no clock source and LEDs were off.

I also tried running the chip with no soft device present.

Is this expected since I'm not using the recommended 32.768KHz external crystal?

Thanks in advance!

[Jørgen Holmefjord]

Hi,

If you are seeing 2.5mA current draw, the nRF52810 chip has either not entered System OFF mode correctly (current could correspond with CPU running current if you have DCDC enabled), or the current is drawn by something else on your board.

Did you power cycle the board after programming, to make sure it does not enter Emulated System OFF mode?

You can also check with a minimal application where you only enter System OFF mode after boot, to check that nothing else in your application is preventing you from going to sleep mode.

Best regards,
Jørgen