at32uc3b0512-z2ues ATMEL Corporation, at32uc3b0512-z2ues Datasheet - Page 15

• Manufacturer Part Number: at32uc3b0512-z2ues
• Description: 32-bit Avr Microcontroller
• Manufacturer: ATMEL Corporation

5.6.2
5.6.2.1
32059J–12/2010
Voltage Regulator
Single Power Supply
Figure 5-1.
The AT32UC3B embeds a voltage regulator that converts from 3.3V to 1.8V. The regulator takes
its input voltage from VDDIN, and supplies the output voltage on VDDOUT that should be exter-
nally connected to the 1.8V domains.
Adequate input supply decoupling is mandatory for VDDIN in order to improve startup stability
and reduce source voltage drop. Two input decoupling capacitors must be placed close to the
chip.
Adequate output supply decoupling is mandatory for VDDOUT to reduce ripple and avoid oscil-
lations. The best way to achieve this is to use two capacitors in parallel between VDDOUT and
GND as close to the chip as possible
Figure 5-2.
3.3V
3.3V
1.8V
Single Power Supply
Power Supply
Supply Decoupling
C
C
OUT2
IN2
ADVREF
VDDANA
VDDCORE
VDDIN
VDDOUT
VDDPLL
VDDIO
Regulator
1.8V
C
C
IN1
OUT1
3.3V
1.8
V
VDDIN
VDDOUT
Dual Power Supply
Regulator
1.8V
ADVREF
VDDANA
VDDIO
VDDIN
VDDOUT
VDDCORE
VDDPLL
AT32UC3B
Regulator
1.8V
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