3A Step-Down Switching Regulator
with Programmable Soft Start
POWER MANAGEMENT
Description
The SC4521 is a current mode switching regulator with
an integrated switch, operating at 600kHz with
programmable soft start and enable functions. The
integrated switch allows for cost effective low power
solutions (peak switch current 3 amps). High frequency
operation allows for very small passive components.
Current mode operation allows for fast dynamic response
and instantaneous duty cycle adjustment as the input
varies (ideal for CPE applications where the input is a
wall plug power).
The low shutdown current makes it ideal for portable
applications where battery life is important.
The SC4521 is an 600kHz switching regulator with a low
pin count.
The SC4521 allows customers to use large capacitive
loads because its programmable soft start limits the dv/
dt of the output at start up.
SC4521
Features
Wide operating voltage range: 4.4V to 24V
Integrated 3 Amp switch
600kHz frequency of operation
Programmable soft start funchion
Current mode control
Precision enable threshold
SO-8 EDP Lead-free package, fully WEEE and RoHS
compliant
Applications
XDSL modems
CPE equipment
DC-DC point of load applications
Portable equipment
Digtial consumer electronics
Typical Application Circuit
D1
1
V
IN
Enable
C3
2
5
8
BST
IN
EN
SS
SW
3
6
C1
L1
V
OUT
SC4521
GND
4
FB
COMP
R1
7
D2
R2
C2
C6
C4
R3
Revision: October 5, 2007
1
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