REV. B

–8–

ADP3300

Constant Dropout Post Regulator

The circuit in Figure 6 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 15 mW. The ADP3000 used in this circuit is a switching

regulator in the step-up configuration.

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

6-Lead Surface Mount Package

(SOT-23)

1

3

4

5

2

6

0.122 (3.10)

0.106 (2.70)

PIN 1

0.071 (1.80)

0.059 (1.50)

0.118 (3.00)

0.098 (2.50)

0.075

(1.90)

BSC

0.037

(0.95) BSC

0.009 (0.23)

0.003 (0.08)

0.022 (0.55)

0.014 (0.35)

10

0

0.020 (0.50)

0.010 (0.25)

0.006 (0.15)

0.000 (0.00)

0.051 (1.30)

0.035 (0.90)

SEATING

PLANE

0.057 (1.45)

0.035 (0.90)

D1

1N5817

C2

100 F

10V

L1

6.8 H

R1

120

ADP3300-5

IN

SD

OUT

GND

C3

2.2 F

5V @ 50mA

C1

100 F

10V

ADP3000-ADJ

SW1

GND

SW2

FB

R2

30.1k

1%

Q1

2N3906

Q2

2N3906

R4

274k

R3

124k

1%

Figure 6. Constant Dropout Post Regulator

ADP3300–Revision History

Location

Page

Data Sheet changed from REV. A to REV. B.

Edits to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Edits to GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Edits to ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Addition to the ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3