Datasheet

ADP3303
–8–
REV.
ADP3303-5.0
OUT
IN
GND
OUTPUT SELECT
5V
0V
C1
1.0mF
ADP3303-3.3
OUT
IN
GND
C2
0.47mF
V
OUT
= 5V/3.3V
V
IN
= 5.5V TO 12V
SD
SD
Figure 23. 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 24, to increase the
output current to 1 A.
V
IN
= 6V TO 8V V
OUT
= 5V @ 1A
MJE253*
C2
10mF
C1
47mF
R1
50V
*AAVID531002 HEATSINK IS USED
IN
OUT
ERR
GND
SD
ADP3303-5
Figure 24. High Output Current Linear Regulator
Constant Dropout Post Regulator
The circuit in Figure 25 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.
D1
1N5817
C2
100mF
10V
L1
6.8mH
R1
120V
ADP3303-3.3
IN
SD
OUT
GND
C3
2.2mF
3.3V @ 160mA
C1
100mF
10V
ADP3000-ADJ
I
LIM
V
IN
SW1
GND
SW2
FB
V
IN
= 2.5V TO 3.5V
R2
30.1kV
1%
Q1
2N3906
Q2
2N3906
R4
274kV
R3
124kV
1%
Figure 25. Constant Dropout Post Regulator
B