nrf9160 idle current consumption ~500μA

[Niovi.sass]

Hi,

I have nRF9160 DK:

• PCA10090 v0.8.3 
• modem firmware 1.2.3

The specifications says that the minimum consumption current is 7µA. So I flash a hex file  which shuts down the modem and puts the chip to system OFF mode which I find it here and I measure consumption with STM32 Nucleo expansion board and it was ~500μA.

Also, I tried a very simple program

main.c

#include <zephyr.h>

void main()
{
	k_cpu_idle();

}

 prj.conf

CONFIG_SERIAL=n
CONFIG_AT_HOST_LIBRARY=n
CONFIG_STDOUT_CONSOLE=n
CONFIG_LOG=n

and

spm.conf

 

CONFIG_IS_SPM=y
CONFIG_FW_INFO=y
CONFIG_GPIO=n
CONFIG_SERIAL=n

nrf9160dk_nrf9160.overlay , nrf9160dk_nrf9160ns.overlay

&adc{
	status ="disabled";
};

&i2c1{
	status ="disabled";
};

&uart1{
	status ="disabled";
};

&i2c2{
	status ="disabled";
};

&uart2{
	status ="disabled";
};

&spi1{
	status ="disabled";
};

&spi2{
	status ="disabled";
};

&spi3{
	status ="disabled";
};

&uart0{
	status ="disabled";
};

but still current was ~500μA.

I tested older modem firmware as 1.1.0,1.1.1 and 1.2.0 also current ~500μA.

any suggestions?

Thanks in advanced,

Niovi.   

[Simon]

Can you upload the files <sample>/build/zephyr/.config and <sample>/build/spm/zephyr/.config, then we can see what Kconfigs are actually being set. It would be interesting to see if CONFIG_SERIAL=y is set in any of them. If you have more child images, can you check the .config of them as well (e.g. <sample>/build/mcuboot/zephyr/.config)?

If the .config's looks fine, would you be able to zip your application and send it over? Then I'll test it on my nRF91 DK.

Best regards,

Simon

[Niovi.sass]

Thanks for the response. In both files <sample>/build/zephyr/.config and <sample>/build/spm/zephyr/.config said

# CONFIG_SERIAL is not set.

Here is my application.
2744.test.zip

Thanks in advanced,

Niovi.

[Simon]

Thanks. I'll take a look at it tomorrow.

[Simon]

I built and flashed your sample using west build -b nrf9160dk_nrf9160ns && west flash and I measured a current of 7.57uA using the PPK2 and an nRF9160DK v0.8.2. I measured a current of 6.61uA using an nRF9160DK v0.9.0. I don't have a v0.8.3 at hand at the moment.

I also tested the system off hex file from Getting started with current measurements on the nRF9160, and measure a current of 6.23uA, which is not as low as the system OFF current in the product specification for some reason, but at least not 500uA.

Could you explain your measurement setup in more details.

[Niovi.sass]

Thank you for the response. I built and flash my application and slide switch SW10 to the EXT position to disable switch U25.

Also  two weeks ago I upgrade to MFW 1.3.0 and downgrade again back to mfw 1.2.0 because the device is  Revision 1 and as far as I understand it is not compatible . Could this be the reason for not getting the right current measurement ? 

Thanks in advanced. 

Best regards,

Niovi

[Simon]

Try to cut SB44 and follow the guide by Bjørn here (which covers the setup for older nRF9160 DKs): https://devzone.nordicsemi.com/f/nordic-q-a/42387/instructions-for-setting-up-9160-dk-for-current-measurement-are-confusing/166460#166460 

Niovi.sass said:

Also  two weeks ago I upgrade to MFW 1.3.0 and downgrade again back to mfw 1.2.0 because the device is  Revision 1 and as far as I understand it is not compatible . Could this be the reason for not getting the right current measurement ?

Modem fw 1.3.0 works with rev1, but that combo will not get certified with any operators. When you transition from 1.3.0 to 1.2.x, you loose all the certificates that are stored in the modem, so we don't recommend doing so. However, this should not affect the current consumption, as far as I know, I think that 1.3.0 uses less current.

Best regards,

Simon

[Niovi.sass]

Thank you for your reply. I tried and measured a current of ~90μΑ better than 500μΑ but still not 7μA.

Thanks in advanced,

Niovi.