SC4521 Datasheet, PDF (1/18 Pages) Semtech Corporation – 3A Step-Down Switching Regulator with Programmable Soft Start

SC4521
3A Step-Down Switching Regulator
with Programmable Soft Start
POWER MANAGEMENT
Description
Features
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.
‹ 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
The SC4521 allows customers to use large capacitive
loads because its programmable soft start limits the dv/
dt of the output at start up.
Typical Application Circuit
D1
V_IN
Enable
C3
2
IN
5
EN
8
SS
C6
1
BST
3
SW
SC4521
6
FB
GND
4
7
COMP
C4
R3
C1
L1
D2
V_OUT
R1
C2
R2
Revision: October 5, 2007
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