Data Sheet

NUC123
May 3, 2017 Page 39 of 99 Rev.2.04
NUC123 SERIES DATASHEET
6.2.4 System Power Distribution
In this chip, power distribution is divided into three segments:
 Analog power from AV
DD
and AV
SS
provides the power for analog components
operation.
 Digital power from V
DD
and V
SS
supplies the power to the internal regulator which
provides a fixed 1.8 V power for digital operation and I/O pins.
 USB transceiver power from VBUS offers the power for operating the USB
transceiver.
The outputs of internal voltage regulators, LDO and USB_VDD33_CAP, require an external
capacitor which should be located close to the corresponding pin. Analog power (AV
DD
) should be
the same voltage level of the digital power (V
DD
). Figure 6-8 shows the power distribution of the
NuMicro
®
NUC123 series.
V
DD
to 1.8V
LDO
USB
Transceiver
5V to 3.3V LDO
PLL
10-bit
ADC
Brown-
out
Detector
POR50
Low
Voltage
Reset
FLASH
Digital
Logic
3.3V
1.8V
22.1184 MHz
HIRC
Oscillator
AV
DD
V
DD
V
SS
USB_VBUS
USB_VDD33_CAP
USB_D+
USB_D-
LDO_CAP
1uF
1uF
IO cell
GPIO
PV
SS
NUC123
Power
Distribution
SRAM
POR18
10 kHz
LIRC
Oscillator
Figure 6-8 NuMicro
®
NUC123 Power Distribution Diagram