SC4524A
28V 2A Step-Down Switching Regulator
POWER MANAGEMENT
Features
Description
The SC4524A is a constant frequency peak current-mode
step-down switching regulator capable of producing 2A
output current from an input ranging from 3V to 28V. The
switching frequency of the SC4524A is programmable
up to 2MHz, allowing the use of small inductors and
ceramic capacitors for miniaturization, and high input/
output conversion ratio. The SC4524A is suitable for
next generation XDSL modems, high-definition TVs and
various point of load applications.
Peak current-mode PWM control employed in the
SC4524A achieves fast transient response with simple loop
compensation. Cycle-by-cycle current limiting and hiccup
overload protection reduces power dissipation during
output overload. Soft-start function reduces input start-
up current and prevents the output from overshooting
during power-up.
The SC4524A is available in SOIC-8 EDP package.
Wide input range: 3V to 28V
2A Output Current
200kHz to 2MHz Programmable Frequency
Precision V Feedback Voltage
Peak Current-Mode Control
Cycle-by-Cycle Current Limiting
Hiccup Overload Protection with Frequency Foldback
Soft-Start and Enable
Thermal Shutdown
Thermally Enhanced 8-pin SOIC Package
Fully RoHS and WEEE compliant
Applications
XDSL and Cable Modems
Set Top Boxes
Point of Load Applications
CPE Equipment
DSP Power Supplies
LCD and Plasma TVs
Typical Application Circuit
10V – 28V
C4
2.2mF
D1
1N4148
C1
0.1mF
L1
8.2mH
R4
42.2k
SS270 REV 4
Efficiency
V
90
85
80
5V/2A
OUT
IN
IN
BST
SW
Efficiency (%)
75
70
65
60
55
50
45
40
0
V
IN
= 12V
V
IN
= 24V
SS/EN
SC4524A
FB
COMP
C7
10nF
R7
28.0k
ROSC
GND
D2
20BQ030
R6
10.5k
C2
22mF
C8
10pF
R5
18.2k
C5
2.2nF
L1: Coiltronics DR73-8R2
C2: Murata GRM31CR60J226K
C4: Murata GRM31CR71H225K
0.5
1
1.5
2
Load Current (A)
Figure 1. 1MHz 10V-28V to 5V/2A Step-down Converter
June 26, 2008
Fig.1 Efficiency of the 1MHz 10V-28V to 5V/2A Step-Do
SEMTECH [ SEMTECH CORPORATION ]
