IC STEP-DWN SW REG 2A 16V 8-SOIC

SC4524BSETRT

Manufacturer Part NumberSC4524BSETRT
DescriptionIC STEP-DWN SW REG 2A 16V 8-SOIC
ManufacturerSemtech
TypeStep-Down (Buck)
SC4524BSETRT datasheet
 


Specifications of SC4524BSETRT

Internal Switch(s)YesSynchronous RectifierNo
Number Of Outputs1Current - Output2A
Frequency - Switching300kHz ~ 1.3MHzVoltage - Input3 ~ 18 V
Operating Temperature-40°C ~ 125°CMounting TypeSurface Mount
Package / Case8-SOICLead Free Status / RoHS StatusLead free / RoHS Compliant
Voltage - Output-Power - Output-
Other namesSC4524BSETR  
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POWER MANAGEMENT
Features
Wide input range: 3V to 8V
2A Output Current
200kHz to 2MHz Programmable Frequency
Precision V Feedback Voltage
Peak Current-Mode Control
Cycle-by-Cycle Current Limiting
Hiccup Overload Protection with Frequency Foldback
Soft-Start and Enable
Thermal Shutdown
Thermally Enhanced 8-pin SOIC Package
Fully RoHS and WEEE compliant
Applications
XDSL and Cable Modems
Set Top Boxes
Point of Load Applications
CPE Equipment
DSP Power Supplies
LCD and Plasma TVs
Typical Application Circuit
10V – 16V
V
IN
C4
2.2mF
BST
IN
SW
SC4524B
SS/EN
FB
COMP
ROSC
GND
C7
R7
R5
10nF
18.2k
C8
30.1k
10pF
C5
1nF
L1: Wurth 744 778 9006
C2: Murata GRM31CR60J226K
C4: Murata GRM31CR61E225K
Figure 1. 1MHz 10V-16V to 5V/2A Step-down Converter
June 2, 2008
18V 2A Step-Down Switching Regulator
Description
The SC4524B is a constant frequency peak current-mode
step-down switching regulator capable of producing 2A
output current from an input ranging from 3V to 8V. The
switching frequency of the SC4524B is programmable
up to 2MHz, allowing the use of small inductors and
ceramic capacitors for miniaturization, and high input/
output conversion ratio. The SC4524B is suitable for
next generation XDSL modems, high-definition TVs and
various point of load applications.
Peak current-mode PWM control employed in the
SC4524B achieves fast transient response with simple loop
compensation. Cycle-by-cycle current limiting and hiccup
overload protection reduces power dissipation during
output overload. Soft-start function reduces input start-
up current and prevents the output from overshooting
during power-up.
The SC4524B is available in SOIC-8 EDP package.
SS270 REV 4
D1
90
85
1N4148
C1
80
0.1mF
L1
OUT
75
6.8mH
5V/2A
R4
70
102k
65
60
55
D2
R6
C2
20BQ030
25.5k
22mF
50
45
40
SC4524B
Efficiency
V
= 12V
IN
0
0.5
1
1.5
2
Load Current (A)


SC4524BSETRT Summary of contents

  • Page 1

    POWER MANAGEMENT Features Wide input range 8V  2A Output Current  200kHz to 2MHz Programmable Frequency  Precision V Feedback Voltage  Peak Current-Mode Control  Cycle-by-Cycle Current Limiting  Hiccup Overload Protection with Frequency Foldback  ...

  • Page 2

    ... GND Pin SOIC - EDP) Marking Information yyww=Date code (Example: 0752) xxxxx=Semtech Lot No. (Example: E900) Ordering Information Device SC4524BSETRT BST SC4524BEVB FB Notes: COMP () Available in tape and reel only. A reel contains 2,500 devices. (2) Available in lead-free package only. Device is fully WEEE and RoHS SS/EN compliant ...

  • Page 3

    Absolute Maximum Ratings V Supply Voltage ……………………………… -0.3 to 24V IN BST Voltage ……………………………………………… 40V BST Voltage above SW …………………………………… 24V SS Voltage ……………………………………………-0 Voltage …………………………………………… -0 Voltage ………………………………………… -0 Transient ...

  • Page 4

    Electrical Characteristics (Cont.) Unless otherwise noted 2V 5V BST Parameter Minimum Switch On-time Minimum Switch Off-time Switch Leakage Current Minimum Bootstrap Voltage BST Pin Current Oscillator Switching Frequency Foldback Frequency Soft Start and Overload ...

  • Page 5

    Pin Descriptions SO-8 Pin Name Pin Function Emitter of the internal NPN power transistor. Connect this pin to the inductor, the freewheeling diode and the  SW bootstrap capacitor. Power supply to the regulator also the collector of ...

  • Page 6

    Block Diagram COMP COMP FREQUENCY FREQUENCY FOLDBACK FOLDBACK ROSC ROSC SS/EN SS/ REFERENCE REFERENCE ...

  • Page 7

    Typical Characteristics SC4524A/B Efficiency =3. =2. =1. 1MHz, V =12V ( =20BQ030 0.5 1 1.5 ...

  • Page 8

    Typical Characteristics (Cont.) SS270 REV 6-7 V Thresholds vs Temperature IN 3.0 2.9 Start 2.8 2.7 2.6 (14) UVLO 2.5 2.4 -50 - 100 125 o Temperature ( C) SS270 REV 6-7 V Quiescent Current ...

  • Page 9

    Applications Information Operation The SC4524B is a constant-frequency, peak current-mode, step-down switching regulator with an integrated 8V, 2.6A power NPN transistor. Programmable switching frequency makes the regulator design more flexible. With the peak current-mode control, the double reactive poles of ...

  • Page 10

    Applications Information (Cont.) As the load draws more current from the regulator, the current-limit comparator ILIM (Figure 2) will eventually limit the switch current on a cycle-by-cycle basis. The over-current signal OC goes high, setting the latch B soft-start capacitor ...

  • Page 11

    Applications Information (Cont.) Minimum Off Time Limitation The PWM latch in Figure 2 is reset every cycle by the clock. The clock also turns off the power transistor to refresh the bootstrap capacitor. This minimum off time limits the attainable ...

  • Page 12

    Applications Information (Cont.) diodes should have an average forward current rating at least 2A and a reverse blocking voltage of at least a few volts higher than the input voltage. For switching regulators operating at low duty cycles (i.e. low ...

  • Page 13

    Applications Information (Cont.) CONTROLLER AND SCHOTTKY DIODE CONTROLLER AND SCHOTTKY DIODE REF REF + + Vc Vc PWM PWM EA EA MODULATOR MODULATOR Vramp Vramp COMP COMP ...

  • Page 14

    ⋅ π ⋅ π ...

  • Page 15

    Recommended Component Parameters in Typical Applications Table 4 lists the recommended inductance (L voltages. The inductance is determined by assuming that the ripple current is 35% of load current I parameters are calculated by assuming a 22mF low ESR ceramic ...

  • Page 16

    Typical Application Schematics Figure 10. 1MHz 5V to 3.3V/2A Step-down Converter Figure 11. 500kHz 10V-16V to 1.5V/2A Step-down Converter 1N4148 1N4148 4.7mF 4.7mF 0.1mF ...

  • Page 17

    Typical Performance Characteristics (For A 12V to 5V/2A Step-down Converter with 1MHz Switching Frequency) SS270 REV 6-7 Load Characteristic 0.5 1 1.5 Load Current (A) Figure 12(a). Load Characteristic 5V Output Response ...

  • Page 18

    ... THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Semtech Corporation Power Mangement Products Division 200 Flynn Road, Camarillo, CA 9302 Phone: (805) 498-2 Fax: (805) 498-3804 ...