
13
mikroBoard for ARM 144-pin
MikroElektronika
page
4. Voltage regulator
The microcontroller require dual power supply: 1.8V for CPU and 3.3V for I/O. The board is powered with the 5V power
supply voltage via the CN3 USB connector supplied on the board.
If the board is powered by the development system (EasyARM v6), the function of the voltage regulator remains the
same. In this case, it is necessary to remove jumper J2 (STANDALONE), Figure 4-3.
VCC
VCC
VCC-3.3
VCC-1.8
VIN
VIN
Adjust
REG1
REG2
VOUT
VOUT
MC33269DT-3.3
LM317
1
1
3
3
2
2
E1
E5
E4
E3
10uF
10uF
10uF
10uF
VCC
R16
2K2
R9
220
R10
100
LD1
POWER
C17
100nF
Figure 4-2
: Voltage regulator connection schematic
Figure 4-1
: Voltage regulator
Figure 4-3
: Standalone mode disabled
Figure 4-4
: Standalone mode enabled