1.25MHz, 1.5A Step-Down
Switching Regulator
POWER MANAGEMENT
Description
The SC4517A is a current mode switching regulator with
an integrated switch, operating at 1.25MHz with separate
sync & enable functions. The integrated switch allows
for cost effective low power solutions (peak switch current
1.5 amps). The sync function allows customers to
synchronize to a faster clock in order to avoid frequency
beating in noise sensitive applications. High frequency
of operation allows for very small passive components.
Current mode operation allows for fast dynamic response
& 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 SC4517A is a 1.25MHz switching regulator
synchronizable to a faster frequency from 1.6MHz to
2MHz.
SC4517A
Features
Integrated 1.5 Amp switch
1.25MHz frequency of operation
Current mode controller
Synchronizable to higher frequency up to 2MHz
6µA low shutdown current
MSOP-8 and MLPD-8 Lead-free packages. This
product is fully WEEE and RoHS compliant
Applications
XDSL modems
CPE equipment
DC-DC point of load applications
Portable equipment
Typical Application Circuit
D1
1
VIN
Enable
C3
2
5
8
BST
IN
SW
3
6
7
C1
L1
VOUT
R1
SC4517AXX
EN
SYNC
FB
COMP
GND
4
D2
R2
C2
C4
R3
Revision: December 13, 2006
1
www.semtech.com