EVK-NORA-W1 - User guide
UBX-22002764 - R02
Hardware description
Page 8 of 22
C1-Public
⚠
Only if the power protection circuits are left intact can the USB be safely connected at the same
time as external power. This makes programming of the module easier.
⚠
The EVK USB type C connectors are only capable of handling 5 V input, 12 V is not allowed.
3.2.1
Powering the board
Set the power switch (SW6)
“ON”
to extend the
VBUS
supply to the 3.3 V LDO regulator and power up
the board. The LDO regulator powers the
+3V3, VDD
and
VDD-IO
power rails. The green LED (D1) is
lit when power is applied. See also
Figure 3: EVK schematic - power supply
Figure 4: EVK schematic - IOREF separation
+3V3
(J1 pin 4) can supply external parts with up to 50 mA (max).
IOREF
(J1 pin 2) is the external supply input to the IO voltage level shifters (optional). A protection
diode (Maxim MAX40203AUK) with a voltage drop of 28 mV at 100 mA separates
IOREF
from
+3V3
.
