SC4524 Datasheet, PDF (1/21 Pages) Semtech Corporation – Programmable Frequency, 2A Output 30V Step-Down Switching Regulator

SC4524
Programmable Frequency, 2A Output
30V Step-Down Switching Regulator
POWER MANAGEMENT
Description
Features
The SC4524 is an adjustable frequency peak current-
mode step-down switching regulator with an integrated
2.3A, 30V switch. The SC4524 can be programmed up
to 1.5MHz. This allows the use of small inductor and
ceramic capacitors, resulting in very compact power
supplies. The SC4524 is suitable for next generation XDSL
modems, set-top boxes and point of load applications.
The SC4524 uses peak current-mode PWM control for
ease of compensation. Cycle-by-cycle current limit and
hiccup overload protection reduce power dissipation
during overload. Combined soft start and enable pin not
only eliminates output start up overshoot but also allows
power sequencing.
u Up to 1.5 MHz Programmable Switching Frequency
u 2.3A Integrated Switch
u Wide Input Voltage Range 2.8V to 30V
u Peak Current-Mode Control with Cycle-by-Cycle
Current Limiting
u Hiccup Overload Protection
u Soft-Start and Enable
u Thermal Shutdown
u Thermally Enhanced 8-Pin SOIC Package
u Fully WEEE and RoHS Compliant
The SC4524 is available in SOIC-8 EDP package.
Applications
u XDSL and Cable Modems
u Set-top Boxes
u Point of Load Applications
u CPE Equipment
u DSP Power Supplies
u Disk Drives
Typical Application Circuit
V _IN
24V
IN
SS
BST
C7
22nF
SC4524 SW
C6
22pF
COMP
R5
ROSC
15.4k
C5
470pF
R3
17.4k
FB
GND
D1
C2 1N4148
0.1mF _L1
4.7mH
OUT
R1 ^5V/2A
22.1k
C3
10mF
D2
20BQ030
C1
R2
22mF 5.49k
L1: Coiltronics FP3-4R7
C1: Murata GRM21BR60J226M
C3: Murata GRM32ER71H106K
Efficie ncy
90
85
80
75
70
65
60
55
50
0.0
0.5
1.0
1.5
2.0
Load Current (A)
Revision: December 30th, 2006
Figure 1. 1MHz 24V to 5V/2A Step-down Converter.
1
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