The nRF52840 Dongle can also be configured to be supplied from an external regulated 1.8–3.6 V (max 50 mA) source through the VDD OUT connection point. To enable this, SB2 must be cut and SB1 must be soldered.
CAUTION:
Do not have both SB1 and SB2
connected at the same time as this will damage the nRF52840 SoC.
Figure 1. Configuring 1.8-3.6 V external source
Warning:
Connecting the polarity the wrong way will cause the
nRF52840 Dongle to overheat.