ADP3303 Data Sheet
APPLICATION CIRCUITS
CROSSOVER SWITCH
The circuit in Figure 25 shows that two ADP3303s can be used
to form a mixed supply voltage system. The output switches
between two different levels selected by an external digital
input. Output voltages can be any combination of voltages from
the Ordering Guide.
Figure 25. Crossover Switch
HIGHER OUTPUT CURRENT
The ADP3303 can source up to 200 mA without any heatsink or
pass transistor. If higher current is needed, an appropriate pass
transistor can be used, as in Figure 26, to increase the output
current to 1 A.
Figure 26. High Output Current Linear Regulator
CONSTANT DROPOUT POST REGULATOR
The circuit in Figure 27 provides high precision with low drop-
out for any regulated output voltage. It significantly reduces the
ripple from a switching regulator while providing a constant
dropout voltage, which limits the power dissipation of the LDO
to 60 mW. The ADP3000 used in this circuit is a switching
regulator in the step-up configuration.
Figure 27. Constant Dropout Post Regulator
ADP3303-5.0
OUT
IN
GND
OUTPUT SELECT
5V
0V
C1
1.0µF
ADP3303-3.3
OUT
IN
GND
C2
0.47µF
V
OUT
= 5V/3.3V
V
I
N
= 5.5V TO 12V
S
D
S
D
10335-025
V
IN
= 6V TO 8V V
OUT
= 5V AT
1A
MJE253*
C2
1
0µF
C1
47µF
R1
50Ω
*AAVID531002 HEATSINK IS USED
IN
OUT
ERR
GND
SD
ADP3303-5
10335-026
D1
1N5817
C2
100µF
10V
L1
6.8µH
R1
120Ω
ADP3303-3.3
IN
SD
OUT
GND
C3
2.2µF
3.3V AT 160mA
C1
100µF
10V
ADP3000-AD
J
I
LIM
V
IN
SW1
GND
SW2
FB
V
IN
= 2.5V TO 3.5V
R2
30.1kΩ
1%
Q1
2N3906
Q2
2N3906
R4
274kΩ
R3
124kΩ
1%
10335-027
+
Rev. C | Page 12 of 16
