MP9403

3A, 7V, 250kHz Integrated Synchronous

Step-Down Converter

MP9403 Rev.0.9

www.MonolithicPower.com

1

2/9/2010

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2010 MPS. All Rights Reserved.

The Future of Analog IC Technology

DESCRIPTION

The MP9403 is a monolithic synchronous buck

regulator. The device integrates a 150mΩ

high-side MOSFET and a 100mΩ low-side

MOSFET that provides 3A continuous load

current over input voltage of 4.3V to 7V. Current

mode control provides fast transient response

and cycle-by-cycle current limit.

An adjustable soft-start prevents inrush current

at turn-on. In shutdown mode, the supply

current drops to 1μA.

This device, available in an 8-pin SOIC

package with exposed pad, provides a very

compact system solution with minimal reliance

on external components.

FEATURES

• 3A Output Current

• 4.3V to 7V Operating Input Range

• Integrated MOSFET Switches

• Output Adjustable from 0.80V to 5.50V

• Up to 93% Efficiency

• Programmable Soft-Start

• Stable with Low ESR Ceramic Output Capacitors

• Fixed 250kHz Frequency

• Cycle-by-Cycle Over Current Protection

• Input Under Voltage Lockout

• Thermally Enhanced 8-Pin SOIC Package

APPLICATIONS

• Distributed Power Systems

• Pre-Regulator for Linear Regulators

• Notebook Computers

“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of

Monolithic Power Systems, Inc.

TYPICAL APPLICATION

INPUT

4.3V to 7V

OUTPUT

2.5V

3A

D1

B320

(optional)

C6

(optional)

MP9403

BS

IN

1

2

3

5

6

4

8

7

FB

SW

SS

GND

COMP

EN

Efficiency vs. Load Current

LOAD CURRENT (A)

0

10

20

30

40

50

60

70

80

90

100

0.01

0.1

1

10