nrf9160 DK current measurement clarification. Measuring 40uA in PSM mode instead of 4uA.

RE: nrf9160 DK current measurement clarification. Measuring 40uA in PSM mode instead of 4uA.

Bendik Heiskel — Mon, 13 Feb 2023 11:20:26 GMT

Try using a second PPK or bench power supply to supply VIO_REF with 3.6V.

The extra current consumption you are measuring is coming from this pull-down resistor in the VIO_REF circuit:

When using VDD_nRF as the source the this current draw is included in the current measured by the PPK.

RE: nrf9160 DK current measurement clarification. Measuring 40uA in PSM mode instead of 4uA.

Frikkie Badenhorst — Fri, 10 Feb 2023 14:41:55 GMT

We are measuring the current in source meter mode at a 3.6V, connecting it to P22 and ground (see picture), and we short VDD_nRF and VIO_REF, so indeed we are using VDD_nRF as the source for VIO_REF. Not illustrated in the picture, as that we leave the USB cable connected, and flip the IFMCU DISCONN switch so that the interface MCU is offline.

We dont really understand why on the one devkit (nrf5340) it is required to short the pin, and then on the nrf9160 it is not.

RE: nrf9160 DK current measurement clarification. Measuring 40uA in PSM mode instead of 4uA.

Bendik Heiskel — Fri, 10 Feb 2023 12:59:07 GMT

Hi Frikkie,

Can you show a diagram of how you are measuring the current with the PPK?

I suspect the extra current draw you are measuring is caused by using VDD_nrf as the source for VIO_REF, can you try using a external 3.6V source for VIO_REF?

Best regards,

Bendik