SC4520

Manufacturer Part NumberSC4520
Description3A Step-Down Switching Regulator
ManufacturerSemtech Corporation
SC4520 datasheet
 
1
Page 1
2
Page 2
3
Page 3
4
Page 4
5
Page 5
6
Page 6
7
Page 7
8
Page 8
9
Page 9
10
Page 10
11
12
Page 1/12

Download datasheet (309Kb)Embed
Next
POWER MANAGEMENT
Description
The SC4520 is a current mode switching regulator with
an integrated switch and an adjustable frequency with
enable function. The integrated switch allows for cost-
effective, low power solutions with a peak switch current
of 3 amps. An adjustable high frequency of 100kHz to
600kHz provides for fast dynamic response and
instantaneous duty cycle adjustment as the input varies,
making the device ideal for CPE applications where the
input is a wall plug power. Low shutdown current also
www.DataSheet4U.com
makes the this device an excellent choice for portable
applications where conserving battery life is of prime
concern.
Typical Application Circuit
V
IN
Enable
C3
Revision: December 13, 2006
3A Step-Down Switching Regulator with
Adjustable Switching Frequency
Features
Wide operating voltage range: 4.4V to 24V
Integrated 3 Amp switch
100kHz to 600kHz adjustable frequency operation
Current mode control
Precision enable threshold
SO-8 EDP package. Lead-free product, fully WEEE
and RoHS compliant
Applications
XDSL modems
CPE equipment
DC-DC point of load applications
Portable equipment
Digtial consumer electronics
C1
1
BST
2
3
IN
SW
5
6
SC4520
EN
FB
8
7
FSET
COMP
GND
4
Rosc
C4
R3
1
SC4520
D1
L1
V
OUT
R1
C2
D2
R2
www.semtech.com

SC4520 Summary of contents

  • Page 1

    ... POWER MANAGEMENT Description The SC4520 is a current mode switching regulator with an integrated switch and an adjustable frequency with enable function. The integrated switch allows for cost- effective, low power solutions with a peak switch current of 3 amps. An adjustable high frequency of 100kHz to 600kHz provides for fast dynamic response and ...

  • Page 2

    ... SC4520 ° ° C ° C ° ...

  • Page 3

    ... SC4520 µ µ µ µ ...

  • Page 4

    ... SC4520 ...

  • Page 5

    ... Rosc = Duty Cycle (%) ISEN ISEN 40m 40m BST BST POWER POWER TRANSISTOR TRANSISTOR SOFT START SOFT START GND GND OL OL HICCUP HICCUP FB FB ILIM @-40C ILIM @25C ILIM @125C 80 100 SC4520 www.semtech.com ...

  • Page 6

    ... Enable Pulling and holding the EN pin below 0.4V activates the shut down mode of the SC4520 which reduces the input supply current to less than 150 mode, the switch is turned off. The SC4520 is turned on if the EN pin is pulled high. 2006 Semtech Corp. Oscillator The external resistor connected to the FSET pin sets the PWM frequency from 100kHz to 600kHz ...

  • Page 7

    ... The first one is the required ESR (Equivalent Series Resistance) which should be low enough to reduce the output voltage deviation during load changes. The second one is the required capacitance, which should be high enough to hold up the output voltage. Before the SC4520 regulates the inductor current to a new value during ...

  • Page 8

    ... Its maximum repetitive reverse block voltage has to be higher than the input voltage of the SC4520. A low forward conduction drop is also required to increase the overall efficiency. The freewheeling diode should be ...

  • Page 9

    ... V I diode F Loop Compensation Design The SC4520 has an internal error amplifier and requires a compensation network to connect between the COMP pin and GND pin as shown in Figure 3. The compensation network includes C4, C5 and R3. R1 and R2 are used to program the output voltage according to: ...

  • Page 10

    ... Connect the ground of the feedback divider and the compensation components directly to the GND pin of the SC4520 by using a separate ground trace. 8. Connect Pin large copper area to remove the IC heat and increase the power capability of the SC4520. A few feedthrough holes are required to ...

  • Page 11

    ... SC4520 V V =5V = 10u 10u / . www.semtech.com ...

  • Page 12

    ... (L1) A DETAIL A -H- DIMENSIONS 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 SC4520 www.semtech.com ...