External LDOVDD12 in the NUC505 can be powered from an external LDO or internal LDO.
VDD12 in the NUC505 is connected to an external 1.2V, and LDO_CAP connects a 4.7uF capacitor to ground
![Image](http://www.nuvoton.com/export/sites/nuvoton/images/Support/FAQ179_I.png)
Internal LDO
LDO_CAP in the NUC505 is first connected to the 4.7uF capacitor, and then connected to VDD12.
![Image](http://www.nuvoton.com/export/sites/nuvoton/images/Support/FAQ179_II.png)
Note:
- LDO_CAP: LDO output pin, DC 1.2V.
- VDD12: I/O power supply pin, DC 1.2V.
The NUC505 power distribution diagram is shown below. LDO_CAP needs to be connected to the 4.7uF capacitor first and then ground; if VDD12 needs to be powered internally, LDO_CAP is connected to the 4.7uF capacitor first, and then connected to VDD12.
![Image](http://www.nuvoton.com/export/sites/nuvoton/images/Support/FAQ179_III.png)