SC4524

Manufacturer Part NumberSC4524
Description2A Output 30V Step-Down Switching Regulator
ManufacturerSemtech Corporation
SC4524 datasheet
 
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POWER MANAGEMENT
Description
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
www.DataSheet4U.com
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.
The SC4524 is available in SOIC-8 EDP package.
Typical Application Circuit
V IN
24V
IN
SS
BST
C7
22nF
SC4524
COMP
ROSC
GND
R5
15.4k
C6
22pF
R3
C5
17.4k
470pF
L1: Coiltronics FP3-4R7
Revision: December 30th, 2006
Programmable Frequency, 2A Output
30V Step-Down Switching Regulator
Features
u
u
u
u
u
u
u
u
u
Applications
u
u
u
u
u
u
D1
C2
1N4148
0.1mF
L1
OUT
SW
4.7mH
5V/2A
R1
22.1k
FB
D2
C3
R2
C1
20BQ030
5.49k
10mF
22mF
C1: Murata GRM21BR60J226M
C3: Murata GRM32ER71H106K
Figure 1. 1MHz 24V to 5V/2A Step-down Converter.
1
Up to 1.5 MHz Programmable Switching Frequency
2.3A Integrated Switch
Wide Input Voltage Range 2.8V to 30V
Peak Current-Mode Control with Cycle-by-Cycle
Current Limiting
Hiccup Overload Protection
Soft-Start and Enable
Thermal Shutdown
Thermally Enhanced 8-Pin SOIC Package
Fully WEEE and RoHS Compliant
XDSL and Cable Modems
Set-top Boxes
Point of Load Applications
CPE Equipment
DSP Power Supplies
Disk Drives
Efficiency
90
85
80
75
70
65
60
55
50
0.0
0.5
1.0
Load Current (A)
SC4524
1.5
2.0
www.semtech.com

SC4524 Summary of contents

  • Page 1

    ... 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 www ...

  • Page 2

    ... SC4524 ° C ° ° ° C ° C ° ...

  • Page 3

    ... SC4524 µ A µ µ ...

  • Page 4

    ... SC4524 ...

  • Page 5

    ... Figure 3. Details of the Soft-Start and Overload Hiccup Control Circuit 2006 Semtech Corp SLOPE COMP + S PWM - R 1V 0.7V REFERENCE FAULT & THERMA L SHUTDOW N SLO PE COMP SLOPE COMP CLK OSCILLATOR Figure 2. SC4524 Functional Diagram + + - - 0.7V 0.7V 1.8mA 1.8mA 1V/2 V 1V/2 V 2.6mA 2.6mA 5 SC4524 VIN 2 + ISEN - 6.3mW + 20m V ...

  • Page 6

    ... Ur €ƒr …h‡ˆ…r Ã8 Ur € ƒr … h ‡ˆ…r à € ƒr … h ‡ˆ…r à €  à ‡  r … …  ˆ 8 à  à ‡ † ‚  ‚    TT à TT     SC4524    66 ...

  • Page 7

    ... &   ã    SC4524 # " Ã2Ã!$ƒ " A7ÃP‰ r …y‚hqÃUu…r†u‚yqà ‰ †ÃU r €ƒr …h‡ˆ…r               Ur € ...

  • Page 8

    ... W ã SC4524 ...

  • Page 9

    ... D 287 = 287 = 287 = W ¼ ¼ ¼ D 287 = 287 ã à à à ÔÏ ÔÏ    †    à        Ur €ƒr …h ‡ˆ…r Ã8 SC4524  ...

  • Page 10

    ...  .+] .   .+]  &(6 SC4524 - - - = D 287 / ...

  • Page 11

    ... ¼ www.DataSheet4U.com  = -  ¼ 287 W ã ¼ ¼ , 287 =  Ë Û Ì Ì Ü Ü 287 / Í Ý 287 ¼ 287 = + = m m SC4524 m D ...

  • Page 12

    ... D BST + 6: & %67 = & %67 SC4524   & % 5(&7 b              Ur €ƒr …h ‡ˆ…rÃ8 b %67 ' 5(&7 ...

  • Page 13

    ... Since V OUT >2.5V) to maximize efficiency. In general efficiency T ON penalty increases as D decreases. . The energy loss b Figure 7 summarizes various ways of bootstrapping the OUT ON for a power SC4524. A fast switching PN diode (such as 1N4148 or b DBST CBST VIN VOUT D RECT = - > 2.5V CBST VIN ...

  • Page 14

    ... Figure 7(c) reduces the maximum BST pin voltage. The BST pin voltage should not exceed its absolute maximum rating of 42V. Figures 7(d) and (e) show how to bootstrap the SC4524 from a second power supply V Since the inductor current charges C circuit requires some minimum load current to get going. ...

  • Page 15

    ... Figure 9(b). 2006 Semtech Corp. Overload / Short-Circuit Protection The current limit comparator in the SC4524 limits the peak inductor current to 3.2A (typical). The regulator output voltage will fall if the load is increased above the current limit. If overload is detected (the output voltage falls below 70% of the set voltage), then the regulator will be shut off. An internal 0.8µ ...

  • Page 16

    ... W 287 w   287  287  Î Þ Ë Û Ì Ì Ü Ü Ï ß ÔÏ Í Ý Ð à 287      ( ) +   ¼ + >> >> & SC4524 & ...

  • Page 17

    ... Figure 10. Simplified Control Loop Equivalent Circuit OUT OUT Control-to-Output Transfer Function . OUT V OUT ESR R OUT C11 COMP v OUT SC4524 www.semtech.com ...

  • Page 18

    ... I5  >> 5 ÔÏ SC4524 287 ...

  • Page 19

    ... N Û ™ Ì Ü Ì Ü ¼  Í Ý    ¼ ¼ p ™   ¼ p ™ ¼ www.DataSheet4U.com ã ¼  ™ ¼  ¼ ™    ™ SC4524 ...

  • Page 20

    ... G‚h qà 8ˆ… …r ‡Ã6 G‚h qà 8ˆ… …r ‡Ã6 SC4524 (IILFLHQF È Ã  ’  ...

  • Page 21

    ... 0° 8° 0° 8° aaa .004 0.10 bbb .010 0.25 ccc .008 0. GAGE PLANE 0. (L1) A DETAIL A -H- DIMENSIONS DIM INCHES MILLIMETERS (.205) (5.20 .134 3.40 E .201 5.10 F .101 2.56 G .118 3.00 P .050 1.27 X .024 0.60 Y .087 2.20 Z .291 7.40 SC4524 www.semtech.com ...