Hardware description
1.
USB
2.
P20
3.
P21
This means that if power is connected to more than one the interfaces, the higher priority interface will be
chosen to supply the DK.
The supply voltage is then routed through the ON/OFF switch (
SW8
) to the common rail VSUPPLY, which
acts as the source for the supply voltage regulators for the circuitry on the DK.
The supply flows from VOUT to VIN, which is correct. The body diode of the internal transistor powers the
VSUPPLY net, which supplies the gates controlling the enable signal of the switches.
The power switches will introduce a small voltage drop between the power source connected to the DK
and the VSUPPLY. To avoid this, the power switches can be bypassed by shorting one of the solder bridges
as shown in the following table:
Power source
Power switch bypass
Voltage level
USB connector (J6)
SB29
5 V
External supply (P21)
SB30
3.0 V–5.5 V
VIN 3–5 V (P20)
SB31
3.0 V–5.5 V
Table 2: Bypassing power switch
Note:
Connect only one power source at a time in this case. Shorting the solder bridges removes
the reverse voltage protection.
4.3.1 nRF9160 supply
The nRF9160 has a supply range of 3.0–5.5 V and is directly powered by the VSUPPLY rail.
4.3.2 VDD supply rail
VDD is the main supply for the rest of the circuitry on the nRF9160 DK. It is regulated down from VSUPPLY
by a buck regulator (
U27
).
Figure 10: VDD buck regulator and selection switch
You can set the VDD voltage to 1.8 V (default) or 3 V with
SW9
. Running 3 V
with heavy load may
degrade the LTE RF performance. A third option for customizing VDD voltage level is applying a custom
4418_1216
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