nRF52 DK v1.1.x

Power supply

The nRF52 Development Kit board has three power options: 5 V from the USB, external power supply, and coin cell battery.

Figure 1. Power supply options

The 5 V from the USB is regulated down to 3.3 V through an on-board voltage regulator. The battery and external power supply are not regulated. The power sources are routed through a set of diodes (D1A, D1B, and D1C) for reverse voltage protection, where the circuit is supplied from the source with the highest voltage.

Important: When USB is not powered, the Interface MCU is in dormant state and will draw an additional current of ~ 20 μA in order to maintain the reset button functionality. This will affect board current consumption, but not the nRF52832 current measurements, as described in the Measuring current section.
Figure 2. Power supply circuitry

The reverse voltage protection diodes will add a voltage drop to the supply voltage of the circuit. To avoid this voltage drop, the diodes can be bypassed by shorting one or more solder bridges.

Table 1. Protection diode bypass solder bridges
Power source Protection bypass Voltage level
USB SB10 3.3 V
Coin-cell battery SB11 Battery
External supply SB12 1.7 V - 3.6 V
Figure 3. Protection diode bypass solder bridges
Important: Connect only one power source at the time. Shorting the solder bridges removes the reverse voltage protection.

Documentation feedback | Developer Zone | Subscribe | Updated 2017-02-16