Ublox EVK-NORA-W10, User Manual, Page: 7 / 22

EVK-NORA-W1 - User guide
UBX-22002764 - R01 Hardware description Page 7 of 22
C1-Public
3 Hardware description
Design files for the EVK-NORA-W10 PCB may be requested from your local u-blox support team .
3.1 Power
The EVK-NORA-W1 has three possible power sources, as listed below:
• USB from the debug interface
• USB peripheral on the NORA-W1 itself
•
2.54 mm pitch pin header (J1 pin-8) for sup 5 V [ 3.6 – 5.5 V]
Each of the three power sources are separated via a Schottky diode (D1 – D3, MBR120VLSFT3G). This
prevents reverse voltage to any of the other supplies thus the power sources can be connected
simultaneously.
⚠
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.
3.1.1 Powering the board
By moving the power switch to “ON” VBUS is fed into the 3.3 V LDO regulator and the board is
powered-up. This is indicated by the power LED D10 (green) lights up. The LDO regulator powers the
+3V3, VDD , and VDD-IO power rails.
Figure 2: EVK schematic - power supply
Figure 3: EVK schematic - IOREF separation
+3V3 (J1 pin 4) can source max 50 mA to supply external parts.
IOREF (J1 pin 2) is the external supply input to the IO voltage level shifters (optional). It is separated
from +3V3 with a protection diode (Maxim MAX40203AUK) having voltage drop of 28 mV at 100 mA.