SYNCHRONOUS DC/DC CONTROLLER FOR
DISTRIBUTED POWER SUPPLY APPLICATIONS
SC1102
September 5, 2000
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
FEATURES
The SC1102 is a low-cost, full featured, synchronous
voltage-mode controller designed for use in single
ended power supply applications where efficiency is of
primary concern. Synchronous operation allows for the
elimination of heat sinks in many applications. The
SC1102 is ideal for implementing DC/DC converters
needed to power advanced microprocessors in low
cost systems, or in distributed power applications
where efficiency is important. Internal level-shift, high-
side drive circuitry, and preset shoot-thru control, al-
lows the use of inexpensive N-channel power switches.
•
•
•
•
•
•
•
1.265V Reference available
Synchronous operation
Over current fault monitor
On-chip power good and OVP functions
Small size with minimum external components
Soft Start
RDS(ON) Current sensing
APPLICATIONS
•
•
•
Microprocessor core supply
Low cost synchronous applications
Voltage Regulator Modules (VRM)
SC1102 features include temperature compensated
voltage reference, triangle wave oscillator and current
sense comparator circuitry. Power good signaling,
shutdown, and over voltage protection are also pro-
vided.
ORDERING INFORMATION
DEVICE(1)
SC1102CSTR
SC1102EVB
PACKAGE
TEMP. RANGE (TJ)
The SC1102 operates at a fixed 200kHz, providing an
optimum compromise between efficiency, external
component size, and cost.
SO-14
0 - 125°C
Evaluation Board
Note:
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
APPLICATION CIRCUIT
Typical Distributed Power Supply
+5V
+
R4
10
C6
680/6.3V
C5
10.0
C7
C8
Vin 5V
R1
1k
R2
U1
C1
0.1
680/6.3V
680/6.3V
SC1102
C2
0.1
_
1
2
3
4
5
6
7
14
13
12
11
10
9
VCC
GND
SS/SHDN
VREF
PWRGD
OVP
C3
0.1
SHDN
VREF
PWRGD
OVP
R3
1k
R8
124*
OCSET
PHASE
DRVH
PGND
SENSE
BSTH
R7
127
+12V
C4
1.0
D1
MBR0520
Q1
L1
STP40NE
2uH
BSTL
+
R5
3.9
Q2
STP40NE
8
DRVL
C9
C10
180/4V
C11
180/4V
C12
180/4V
C13
180/4V
Vout=2.5V*
180/4V
R6
2.2
_
NOTE:
*) Vout = 1.265 x (1+R8/R7)
Figure 1.
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320