SC1103 Semtech Corporation, SC1103 Datasheet - Page 6

• Manufacturer Part Number: SC1103
• Description: VOLTAGE MODE PWM CONTROLLER
• Manufacturer: Semtech Corporation

be decoupled directly to GND by a 0.1 F ceramic ca-
pacitor, trace lengths should be as short as possible.
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 SC1103 should
run parallel and close to each other. The 0.1µF capaci-
tor 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
SC1103 with the bottom resistor (Rb) returned to
ground at the GND pin.
TYPICAL APPLICATIONS
Fig. 8: 5V to 3.3V @ 8A
© 2000 SEMTECH CORP.
PRELIMINARY - February 29, 2000
+5V
GND
+12V
R1
10
C5
0.1
C1
0.1
R2
1k
R3
1k
C2
1500/6.3V
C6
0.1
C3
1500/6.3V
1
2
3
4
VCC
Cs(-)
Cs(+)
PGND
SC1103
U1
GND
BST
DH
FB
VOLTAGE MODE PWM CONTROLLER
8
7
6
5
IRL3103S
Q1
C7
0.01
R4
2.7
C8
0.1
Under Voltage Lockout
The under voltage lockout circuit of the SC1103 as-
sures that the high-side MOSFET driver outputs remain
in the off state whenever the supply voltage drops be-
low set parameters. Lockout occurs if V
3.8V. Normal operation resumes once V
3.8V.
MBRB1530CT
D1
5.6uH
L1
652 MITCHELL ROAD NEWBURY PARK CA
0.012
R5
C9
1500/6.3
C10
1500/6.3
C11
1500/6.3V
CC
C12
0.1
CC
falls below
rises above
SC1103
R6
205
124
R7
+3.3V
GND
6