User Manual

nRF51 Development Kit User Guide v1.0
Page 13
Figure 8 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 2 Protection diode bypass solder bridges
Figure 9 Protection diode bypass solder bridges
Note: By shorting the solder bridges, the reverse voltage protection is removed, and you must make
sure to connect only one power source at the time.
Power source Protection bypass Voltage level
USB SB10 3.3 V
Coin-cell battery SB11 Battery
External supply SB12 1.8 V - 3.6 V
C18
100nF
C17
1.0μF
C16
1.0μF
+
Bat1
Bat Holder CR2032
Vin
GND
Vout
U3
AP7333-33SAG-7
D1A
SD103ATW-7-F
D1B
SD103ATW-7-F
D1C
SD103ATW-7-F
VIO
R6
N.C.
SB9
VDD_nRF
SW6
Switch
1
2
P21
Pin List 1x2, Angled
VBUS
SB10
SB11
SB12
TP11
1 2
P22
Pin List 1x2, Angled
Power switchUSB power voltage regulator nRF current measurementReverse voltage protection
USB_DETECT
V5VV5V
SB10
SB11
SB12