© 2000 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

LOW VOLTAGE, BOOST DC-DC

CONTROLLER

SC1408

August 22, 2000

5

Fig. 1: Typical Application - Boost Configuration

+

C3

100uF

C5

0.1uF

D1

B130T

R3

31.6k

Vin=3.3V

C9

(1)

U1

SC1408IS

8

1

2

3

4

5

6

7

ISENSE

GATE

BST

FB

SHDN

REF

AGND

GND

+

C8

100uF

R4

10.0k

COILCRAFT DO3316P-223

+

C2

100uF

Q1

IRLR024N

L1

22uH

(1) See Component Selection

R2

0.05Ohm

Vout=5V

Fig. 2: Typical Application - Buck/Boost (SEPIC) Configuration

C9

(1)

R2

0.05Ohm

C4

0.1uF

D1

B130T

Vin=2.7V to 6V

D2

1N4148

+

C1

100uF

+

C2

100uF

L1A 22uH

1

2

L1A/L1B IS COUPLED INDUCTOR

PULSE PE-53718 OR

EQUIVALENT

R4

10.0k

Q1

IRLL3303

+

C3

100uF

U1

SC1408IS

8

1

2

3

4

5

6

7

ISENSE

GATE

BST

FB

SHDN

REF

AGND

GND

Vout=5V

(1) See Component Selection

R3

31.6k

L1B

22uH

4

3

+

C8

100uF

C5

0.1uF