SC1101

© 2000 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

VOLTAGE MODE PWM CONTROLLER

February 29, 2000

6

7) The Current Sense resistor and the divider across it

should form as small a loop as possible, the traces run-

ning back to CS(+) and CS(-) on the SC1101 should run

parallel and close to each other. The 0.1

µF capacitor

should be mounted as close to the CS(+) and CS(-) pins

as possible.

8) To minimize noise pickup at the sensitive FB pin, the

feedback resistors should both be close to the SC1101

with the bottom resistor (Rb) returned to ground at the

GND pin.

Under Voltage Lockout

The under voltage lockout circuit of the SC1101 assures

that the high-side MOSFET driver outputs remain in the

off state whenever the supply voltage drops below set

parameters. Lockout occurs if V

mal operation resumes once V

C2-C7 - AVX: TPSE227M010S0100

Q1, D1 - International Rectifier

L1- Coilcraft: DO5022P-392HC

+3.3V

+12V

GND

VOUT

+5V

C1

0.1uF

R1

6mOhm

R3

10

C9

0.1uF

C10

0.1uF

+

C2

220uF

J1

1

J3

1

J4

1

Cx

0.01

C8

0.1uF

R2

24

J2

1

C6

0.1uF

U1

SC1101CS

GND

8

VCC

1

CS(-)

2

CS(+)

3

PGND

4

DH

5

BST

6

FB

7

R4

124

+

C3

220uF

+

C4

220uF

+

C5

220uF

Q1

IRL2203S

L1

J5

1

D1

32CTQ030S

C7

0.01uF

J6

1

R5

1k

R6

1k

Fig. 6: GTL+ 3.3V to 1.5V 8A Application

TYPICAL APPLICATIONS