POWER MANAGEMENT

1

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SC4521

3A Step-Down Switching Regulator

with Programmable Soft Start

Features

Revision: October 5, 2007

The SC4521 is a current mode switching regulator with

an integrated switch, operating at 600kHz with

programmable soft start and enable functions. The

integrated switch allows for cost effective low power

solutions (peak switch current 3 amps). High frequency

operation allows for very small passive components.

Current mode operation allows for fast dynamic response

and 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 SC4521 is an 600kHz switching regulator with a low

pin count.

The SC4521 allows customers to use large capacitive

loads because its programmable soft start limits the dv/

dt of the output at start up.

Wide operating voltage range: 4.4V to 24V

Integrated 3 Amp switch

600kHz frequency of operation

Programmable soft start funchion

Current mode control

Precision enable threshold

SO-8 EDP Lead-free package, fully WEEE and RoHS

compliant

XDSL modems

CPE equipment

DC-DC point of load applications

Portable equipment

Digtial consumer electronics

C1

D2

R3

D1

L1

C2

BST

1

IN

2

SW

3

GND

4

EN

5

FB

6

COMP

7

SS

8

Enable

C4

C3

R2

R1

SC4521

C6

C1

D2

R3

D1

L1

C2

BST

1

IN

2

SW

3

GND

4

EN

5

FB

6

COMP

7

SS

8

Enable

C4

C3

R2

R1

SC4521

C6

Typical Application Circuit

Applications

Description