The nRF only mode disconnects the power supply of the interface MCU, the external memory, and the LEDs as well as disconnects the signal lines between the nRF5340 System on Chip (SoC) and the interface MCU using analog switches.
This is done to isolate the chip on the Preview Development Kit (PDK) as much as possible, and can be of use when measuring currents on low-power applications.
The power supply of the external memory can be changed to maintain operation in the nRF only mode. See External memory for more information.
Figure 1. nRF only switch (SW6)
